I used to do this during my first real job and was tracking every sandwich I bought, then one of the senior engineers told me to stop wasting time with it and make more money, and then I was enlightened.
25 years ago when my wife and I were poor grad students we had to do this. I tracked everything religiously and she cut coupons for the grocery store. We were generally positive about $100/month at best. Tracking it allowed us to not go negative.
As soon as we got real jobs with a real income, we didn't waste time with that. Our philosophy now is to just make sure that we spend well under our means and not track. We don't penny-pinch, but we still keep some of the grad school "do I really need this?" mentality.
Our normal spending is somewhere under 1/2 of our take-home (including mortgage), so we just don't worry about it and keep saving. It helps that we don't have fancy tastes. It's a nice stress free way of saving and we don't have to get neurotic about tracking every penny either.
I get that people on here don't like subscriptions, and I understand why, but I've been using You Need a Budget for well over a decade, and it is probably the last subscription I'd ever give up.
The automatic import of expenses is so valuable for my family and keeping track of how much we've spent and how much we have left for the month.
We used the fixed-cost version for years beyond when it was officially supported, and it didn't have the automated import, and I don't think I could ever go back to a system that didn't. There were always a few days a month, at least, when I wasn't exactly sure where we were in our expenses.
I'm a huge fan of YNAB. It's a morning routine to log in (really, the tab is always up) and reconcile accounts. The zero-based budgeting method, while not requiring YNAB, is beautifully represented in the software. I'm sure I could use some free software to accomplish the basic tasks but having an associated app my spouse can review for quick decision making is very valuable.
It's made budgeting a tool to accomplish savings, wealth growth, and expense smoothing rather than simply a survival strategy. When you have to deliberately shift funds out of one category to cover another, you really consider the relative priorities.
I dont mind paying for a personal finance tool, but I feel like most of them are made for an average consumer who spends in one currency and needs budgeting. I operate in at least 3 currencies, don’t care about budgeting, and need support for tracking stocks and automatic currency conversions.
The only tools that were able to provide that were GnuCash and PTAs like beancount.
My point is, there is a big segment of people who are not served by existing personal finance tools simply because they operate in more than 1 currency, or have a slightly more complicated setup than envelope budgeting.
I used YNAB since back when they used to just sell the software and maintained a subscription for a little while. I will say that their approach to budgeting has changed the entire way of how I look at money, and even though I have switched to GNU Cash, I have essentially replicated the envelope method there (it requires four entries per transaction instead of the standard two).
For anyone who wants to use this envelope method without paying for YNAB, I recommend checking out Buckets, which is another software that works similarly.
I've been using YNAB 4 (aka YNAB Classic on Android) for some time. I got a new phone, and the phone app finally won't run on the new phone. YNAB 4 is also quite buggy on my Arch based setup (someone maintains a package on AUR using Wine). So I think it's finally time to move on, which I think I'm doing this year.
My only issue with Buckets is that the YNAB importer doesn't take into account that YNAB will take your overspending and take it from your next month's income. I have some bad habits that means I was really using YNAB as more of a financial tracker than an actually budget system. That's my own fault though. The envelope in question comes out to $-10k... That's all my own fault though. It just means I have to massage it into Bucket's system, or start a new budget.
+1, I bought YNAB back when you could - old Windows version that I would run under WINE. I used that until 2025 when I migrated to self-hosted Actual Budget (I run it on fly.io). It does everything I need.
> The key insight is that bank statement PDFs are almost always columnar. Of course, this relies on the PDF having a proper text layer; if your bank sends you scanned images, you’re out of luck (though I’ve yet to encounter one that does). When you convert them to text while preserving the layout, you get something that looks like this:
So I decided to try this out with my bank who's export options are (one of the mentioned slightly silly multi-line format) XLSX or PDF only, and it appears they've done some "encryption" (really a simple substitution cipher and an embedded font with the characters jumbled up so it renders correctly) to the PDF to prevent this. All the marketing text and headers are in the pdftotext output fine but the actual data is all accented and non-printable characters (also if you copy/paste out).
The substitution cipher does seem stable across a few statements, but still seems like less work to work off the XLSX
I remember seeing an online shop that did the whole font substitution to prevent web-scraping of their prices.. I think they even changed the substitution between elements so one couldn't just do a single pass replacement and get the original data back..
I guess nowadays it's very cheap to run a headless browser, screenshot the output, and run it through OCR.. hah, to prevent that they'd have to design their webpage as 1 full screen Captcha..
It appears Tabula also gets the substituted content instead.
What I'm seeing is that for example, POS is substituted to & !ë on every line in every file, etc. I can see by comparing to the rendered PDF for other common text (like my name, the local supermarket, etc) that those all seem to be 1:1 substitutions too.
I like having an archive of PDF statements but the downside is that it’s usually a tedious manual process to download them. There’s so many to track - bank accounts, credit cards, investments, utilities, doctor bills… Every website is different, and they are rarely batch-downloadable. So I tend to be a few months behind at any given moment until I get around to it.
Anyone found a better way to keep on top of downloading statements?
This is neat, but I'm not really convinced this level of granularity makes sense for personal finances? Or at least it does not for me personally. I find that simply entering all my accounts into one big excel once a month more than suffices to keep track of everything. Maybe I make a typo here and there but it doesn't really matter in the grand scheme of things cuz I'm gonna type a new number next month anyway.
I guess it depends on the complexity of ones personal finances? The author had multiple currencies, investments, and who knows what else.
I ran a small business for a while, and I would draw a parallel to that. Once a family's finances hits the complexities of a small business, multiple assets, loans, cars, long term savings, investments, I'd say the granularity is worth it. I would certainly like to try it out.
I really enjoyed reading this, and it is inspirational as it is something I have wanted to do for a long time. And as a software developer, it really appeals to me.
How do you think it compares time-wise to using existing accounting software? Was the time investment worth it to get the control and visibility you now have?
> How do you think it compares time-wise to using existing accounting software?
Author here. I tried various consumer budgeting apps before I ended up building my own (and then going to Beancount). The main problem with every one of the apps I tried is that they don't handle investments well. 99% of my money is invested and having net worth figures which are wildly wrong because the app is only tracking bank accounts really annoyed me. That was the reason I built my own thing in the first place.
> Was the time investment worth it to get the control and visibility you now have?
Absolutely yes. I think it helps me really understand where my money is going, how I can make it work harder etc. Even though the RE part of FIRE doesn't appeal to me, the FI part does and knowing where I stand at all times has been very motivating.
Thank you for taking the time to reply - thank you!
I have question on a more personal front - please feel no obligation to reply.
What impact has having such clear visibility into your accounts had on your relationship with your wife? It feels like it would be a great catalyst for communication, trust and building things if shared finances was a key part of the relationship.
I think this part was the most inspirational - it takes a lot of courage to be that open about finances, even with partners, perhaps especially with partners.
> What impact has having such clear visibility into your accounts had on your relationship with your wife?
That's a great question. Thankfully when it comes to finances we are very aligned in our habits and goals. So we find it very natural to be open because we know that we're both going to be aligned.
Where we differ heavily though is how much we are willing to really getting onto the nitty gritty details. She really likes knowing how our money works but she also has no interest in spending so much time and effort on it.
But that works great because I love this stuff. So every month or so we have a "finances session" where I sit down with her, take her through the books and make sure we're both happy with everything.
Obviously this very much depends on the couple whether this works but it has for us so far!
Would you consider a follow up blog post about how you structure and approach your monthly finance sessions? I understand that it would be well outside of your topics of software engineering, performance and open-source, but I find that the human component of our industry is often missing. An insight into how someone has successfully navigated that would be a wonderful read.
Can somebody explain to me the advantage of double-entry bookkeeping? Is it basically just a "checksum" so it's easier to notice when something is off?
Double-entry accounting models the source and destination of funds. If you keep all of your money in one bank account and neither owe anyone or have anyone that owes you, then double-entry accounting is not necessary because you can record just the one side of every transaction – your bank account is the other side.
However, if you have more than one account or debts, or budgets, then it becomes useful to track both sides of a transaction. If you track both sides of a transaction then you can easily answer questions like:
1. how much money do I have in my investment account?
2. how much debt do I have?
3. how much did I spend on recreational social activities?
You can track debts and investments separately, but then you are still making two entries just in two places.
I think many people have few enough debts and investment account that they track these separately, and the third question, budgeting, can be simplified if each vendor is only ever considered for a single budget, for example, all your flights are part of your vacation budget, and you don't care to break out a flight to a career related conference.
Here is my explanation for "software people who understand databases". The structure of the explanation will be as follows:
1. Explain how you would do simple accounting with a database
2. Point out which indices you'd create for performance
3. Show how the "double entry" part of double entry accounting is about the indices
1. The way you'd do accounting in a database is with two tables: One table for accounts (e.g. your checking account, or the supermarket account, which you don't own) and another table for transactions. The transactions move an amount of money from one account to another, e.g. from your checking account to the supermarket account. Or if you use it for budgeting, you might split your checking account into a groceries account, a rent account etc. (think "categories").
2. For performance, you would create indices based on the accounts in the transaction table, so you could easily check what's going on e.g. in your groceries account or how much you spent at the supermarket.
3. Double entry accounting was formalized in the 15th century, way before computers became a thing, but bound paper books were already somewhat affordable. The way you'd do accounting is like this: During the business day, you would write down your transactions as they happen, into a scrapbook, similar to the transactions table mentioned above. At the end of the day, you'd do the "double entry" part, which means you take your "index" books where each book is about one account and you transcribe each transaction from your scrap book into the two books of the two accounts that are mentioned in the transaction, e.g. if you spent $10 from your groceries account into the supermarket account, you'd double enter that transaction both into your "groceries" book and into your "supermarket" book. Then, when you want to check on how much you spent at the supermarket in a particular month, you could easily look it up in the supermarket book (this would be very tedious when using the scrap book). These account centered books are like the indices in the database mentioned above.
So the double entry part is about clever index building for making it easier and faster to understand what's going on in your accounting system.
Not an accountant, so if I get it wrong someone please correct me. But index fund shares are an asset: something you own. So is your car, your house (if you own it), and your computer. When you buy an asset, you paid a certain price for it. When you sell it, you pay a different price. Until you sell it, though, you don't actually have the money, so it hardly matters what its value is until you sell it. If you buy $100 of an index fund and a year later it has grown by 10%, you don't actually have $110 yet until you sell it. So you just track that you have a certain number of shares of the fund. Let's say each share sells for exactly $20 when you bought them, so you have exactly 5 shares. Later the share price is $22, but you don't have $110 yet, you still have exactly 5 shares. When you sell them, then you'll have $110.
So you record two entries:
January 1st, 2025:
-$100 checking account
+5 shares VFINX at $20 ea
January 1st, 2026:
-5 shares VFINX at $22 ea
+$110 checking account
At this point you have "realized" ("made real") $10 of profit from this asset. You bought it for $100 and sold it for $110, so the IRS wants you to pay taxes on the $10 profit you made. (This is capital gains tax). Until you sold them, some people would consider you to have $10 profit in "unrealized capital gains", but you did not actually have that profit until you sold the shares. This is important to remember, because if you start counting on that $10 profit but then the share price drops because the economy took a hit, suddenly you don't have $110 worth of shares, you have $90 worth of shares, and you'll make a loss if you sell them now. (This is one of the reasons why only the economically illiterate would propose a tax on "unrealized capital gains": that means taxing people for income they have not actually received, but merely could theoretically receive. Which is both immoral and stupid.)
Hope this explanation helps a little. And as I said, if I got something wrong, please correct me and explain how I was wrong; I'm not an accountant. I understand the basic principles, but it's entirely possible I was off on some detail or other.
Accounts (in the accounting sense) are unitless, and refer to whatever meaning we ascribe to them, so we can transfer value from $ to shares, or USD to GBP or whatever.
Lalit describes this I think really well in his article
Yes, it makes it both really simple to spot mistakes and also allows you to easily audit the whole thing after the fact. In corporate contexts it's a straightforward way to make sure your bookies are also honest, just have an external firm look through the whole thing every now and then.
I must have read half a dozen intro-to-accounting books, and it never ever clicked for me. I understood the concepts, the benefits, but it just felt 'wrong'.
It wasn't wrong of course, there is so much history, ingenuity and the invention of double entry accounting, but I just couldn't get my brain to understand it.
The way the concepts settled in my head was: double entry accounting is just an excellent way of modelling a graph with nodes and edges. Accounts are nodes, transfers are edges. Every edge has a source and a destination.
For a paper ledger, each column is graph node, and each row is a graph edge.
That was enough for me to be able to learn the rest of the things I needed for interacting with the accounting world.
But I also realised that that description really only helps a very small part of the population. :D It makes things so much worse for most people.
"Hey could you help me understanding this accounting thing?"
"Sure, but first thing is, let's learn graph theory! You know who Dijkstra right?"
Whole buckets of nope.
But thats a digression from your actual question - whats the point?
It presents a rigid set of rules of recording transfers, everything has to have a from account and to account (i.e. a graph edge), every row must add up to zero.
Because of that, it makes it easy to spot any mistakes in data entry. If any of your rows dont add up to zero - then you've made a mistake.
It's not really a checksum. It can sometimes function as one (everything should sum to zero, if it doesn't then you have a math error), but since most records you make will just have two entries (spent $25 on groceries, remove $25 from checking account) the everything-sums-to-zero feature isn't going to catch math mistakes most of the time, because there is no math to be done on most entries. Rather, the fact that everything sums to zero helps you track things later on.
To explain that, I'll rephrase, in my own words, the restaurant example from the article, because that was a good example of the concept. Let's say you went to a restaurant with two friends and decided to split the $90 bill three ways, but your friends didn't have $30 in cash on them at the time. You put the whole $90 on your credit card, and your friends paid you back $30 each the next week: one on Monday, and one on Wednesday.
In single-entry accounting you might have written the following transactions:
Thursday Jan 1st: $90 restaurant (credit card)
Monday Jan 5th: $30 repaid from Alice (cash)
Wednesday Jan 7th: $30 repaid from Bob (cash)
Thing is, there's nothing to link those transactions together. If you look at these entries three years later, you'll probably be left scratching your head as to why Alice paid you back $30: there's no $30 transaction, so the $90 restaurant transaction won't jump out at you as the reason why Alice paid you back.
But with double-entry bookkeeping, you'd write that as follows:
Thursday Jan 1st:
-$90 restaurant (credit card)
+$30 my share of the restaurant bill (expenses)
+$30 Alice's share of the restaurant bill (money owed to me)
+$30 Bob's share of the restaurant bill (money owed to me)
Monday Jan 5th:
-$30 Alice's share of the restaurant bill (money owed to me)
+$30 cash received (cash)
Wednesday Jan 7th:
-$30 Bob's share of the restaurant bill (money owed to me)
+$30 cash received (cash)
It's not always obvious when you're new to double-entry accounting which entries should be positive or negative, but if you remember the "must add to zero" rule you'll be more likely to get it right. Money flowing into an account is positive, money flowing out of an account is negative. For credit cards, the money flows "out of" your credit card and into the restaurant's ownership, so the sign should be negative. When you pay the credit card bill later, the sign will be positive on the credit card account (and negative on your checking account, thus again adding to zero) because money is flowing out of your checking account and into your credit card account.
Now, look at that double-entry accounting. When you look at the Wednesday Jan 5th entry, and you see that Alice paid you back $30, you'll start searching for a $30 transaction earlier, and you'll pretty quickly find the January 1st and figure out that she owed you $30 because you had paid her share of the restaurant bill on the 1st. And even if the amounts don't line up (let's say she paid you $20 on Jan 5th and $10 on Jan 12th), there's still a "money Alice owes me" category which has a +$30 entry on the 1st, then -$20 on the 5th and -$10 on the 12th, all of which makes it pretty easy to figure out what Alice is paying you back for.
So by recording each entry in at least two places (it's not always exactly two places, e.g. the January 1st expense is recorded in four places total), you get more linkage between the items and it becomes a lot easier to see why the money was going out or coming in.
I used to do this during my first real job and was tracking every sandwich I bought, then one of the senior engineers told me to stop wasting time with it and make more money, and then I was enlightened.
Not that a sandwich will make much difference but you have to remember that employers like their staff to be indebted, it makes them compliant.
Agreed this style of making money may have made sense when the world was more Sane but there’s no way to penny pinch yourself into a house in 2026
25 years ago when my wife and I were poor grad students we had to do this. I tracked everything religiously and she cut coupons for the grocery store. We were generally positive about $100/month at best. Tracking it allowed us to not go negative.
As soon as we got real jobs with a real income, we didn't waste time with that. Our philosophy now is to just make sure that we spend well under our means and not track. We don't penny-pinch, but we still keep some of the grad school "do I really need this?" mentality.
Our normal spending is somewhere under 1/2 of our take-home (including mortgage), so we just don't worry about it and keep saving. It helps that we don't have fancy tastes. It's a nice stress free way of saving and we don't have to get neurotic about tracking every penny either.
I get that people on here don't like subscriptions, and I understand why, but I've been using You Need a Budget for well over a decade, and it is probably the last subscription I'd ever give up.
The automatic import of expenses is so valuable for my family and keeping track of how much we've spent and how much we have left for the month.
We used the fixed-cost version for years beyond when it was officially supported, and it didn't have the automated import, and I don't think I could ever go back to a system that didn't. There were always a few days a month, at least, when I wasn't exactly sure where we were in our expenses.
I'm a huge fan of YNAB. It's a morning routine to log in (really, the tab is always up) and reconcile accounts. The zero-based budgeting method, while not requiring YNAB, is beautifully represented in the software. I'm sure I could use some free software to accomplish the basic tasks but having an associated app my spouse can review for quick decision making is very valuable.
It's made budgeting a tool to accomplish savings, wealth growth, and expense smoothing rather than simply a survival strategy. When you have to deliberately shift funds out of one category to cover another, you really consider the relative priorities.
I dont mind paying for a personal finance tool, but I feel like most of them are made for an average consumer who spends in one currency and needs budgeting. I operate in at least 3 currencies, don’t care about budgeting, and need support for tracking stocks and automatic currency conversions.
The only tools that were able to provide that were GnuCash and PTAs like beancount.
My point is, there is a big segment of people who are not served by existing personal finance tools simply because they operate in more than 1 currency, or have a slightly more complicated setup than envelope budgeting.
I regularly pay with 3 currencies, and YNAB isn't great for that, but it ends up working out because 95% of my spend is in just one.
But, you're right, I have no need for tracking stocks, as I only check in once a year or so, and I can't imagine YNAB would manage that well.
I used YNAB since back when they used to just sell the software and maintained a subscription for a little while. I will say that their approach to budgeting has changed the entire way of how I look at money, and even though I have switched to GNU Cash, I have essentially replicated the envelope method there (it requires four entries per transaction instead of the standard two).
For anyone who wants to use this envelope method without paying for YNAB, I recommend checking out Buckets, which is another software that works similarly.
I've been using YNAB 4 (aka YNAB Classic on Android) for some time. I got a new phone, and the phone app finally won't run on the new phone. YNAB 4 is also quite buggy on my Arch based setup (someone maintains a package on AUR using Wine). So I think it's finally time to move on, which I think I'm doing this year.
My only issue with Buckets is that the YNAB importer doesn't take into account that YNAB will take your overspending and take it from your next month's income. I have some bad habits that means I was really using YNAB as more of a financial tracker than an actually budget system. That's my own fault though. The envelope in question comes out to $-10k... That's all my own fault though. It just means I have to massage it into Bucket's system, or start a new budget.
For a FOSS alternative: Actual budget isn't dissimilar from what YNAB was years ago when it was an on device budgeting software
+1, I bought YNAB back when you could - old Windows version that I would run under WINE. I used that until 2025 when I migrated to self-hosted Actual Budget (I run it on fly.io). It does everything I need.
> The key insight is that bank statement PDFs are almost always columnar. Of course, this relies on the PDF having a proper text layer; if your bank sends you scanned images, you’re out of luck (though I’ve yet to encounter one that does). When you convert them to text while preserving the layout, you get something that looks like this:
So I decided to try this out with my bank who's export options are (one of the mentioned slightly silly multi-line format) XLSX or PDF only, and it appears they've done some "encryption" (really a simple substitution cipher and an embedded font with the characters jumbled up so it renders correctly) to the PDF to prevent this. All the marketing text and headers are in the pdftotext output fine but the actual data is all accented and non-printable characters (also if you copy/paste out).
The substitution cipher does seem stable across a few statements, but still seems like less work to work off the XLSX
I remember seeing an online shop that did the whole font substitution to prevent web-scraping of their prices.. I think they even changed the substitution between elements so one couldn't just do a single pass replacement and get the original data back..
I guess nowadays it's very cheap to run a headless browser, screenshot the output, and run it through OCR.. hah, to prevent that they'd have to design their webpage as 1 full screen Captcha..
That's a ridiculously dumb idea on the bank's part.
Print the PDF to an image. Then use OCR. Then import the output from that instead.
Interesting! You might want to try Tabula in that case.
For that type of "obfuscated" PDFs I've come across, it does well, it's just a lot slower to run than pdf2text.
It appears Tabula also gets the substituted content instead.
What I'm seeing is that for example, POS is substituted to & !ë on every line in every file, etc. I can see by comparing to the rendered PDF for other common text (like my name, the local supermarket, etc) that those all seem to be 1:1 substitutions too.
I like having an archive of PDF statements but the downside is that it’s usually a tedious manual process to download them. There’s so many to track - bank accounts, credit cards, investments, utilities, doctor bills… Every website is different, and they are rarely batch-downloadable. So I tend to be a few months behind at any given moment until I get around to it.
Anyone found a better way to keep on top of downloading statements?
This is neat, but I'm not really convinced this level of granularity makes sense for personal finances? Or at least it does not for me personally. I find that simply entering all my accounts into one big excel once a month more than suffices to keep track of everything. Maybe I make a typo here and there but it doesn't really matter in the grand scheme of things cuz I'm gonna type a new number next month anyway.
I guess it depends on the complexity of ones personal finances? The author had multiple currencies, investments, and who knows what else.
I ran a small business for a while, and I would draw a parallel to that. Once a family's finances hits the complexities of a small business, multiple assets, loans, cars, long term savings, investments, I'd say the granularity is worth it. I would certainly like to try it out.
I really enjoyed reading this, and it is inspirational as it is something I have wanted to do for a long time. And as a software developer, it really appeals to me.
How do you think it compares time-wise to using existing accounting software? Was the time investment worth it to get the control and visibility you now have?
> How do you think it compares time-wise to using existing accounting software?
Author here. I tried various consumer budgeting apps before I ended up building my own (and then going to Beancount). The main problem with every one of the apps I tried is that they don't handle investments well. 99% of my money is invested and having net worth figures which are wildly wrong because the app is only tracking bank accounts really annoyed me. That was the reason I built my own thing in the first place.
> Was the time investment worth it to get the control and visibility you now have?
Absolutely yes. I think it helps me really understand where my money is going, how I can make it work harder etc. Even though the RE part of FIRE doesn't appeal to me, the FI part does and knowing where I stand at all times has been very motivating.
Thank you for taking the time to reply - thank you!
I have question on a more personal front - please feel no obligation to reply.
What impact has having such clear visibility into your accounts had on your relationship with your wife? It feels like it would be a great catalyst for communication, trust and building things if shared finances was a key part of the relationship.
I think this part was the most inspirational - it takes a lot of courage to be that open about finances, even with partners, perhaps especially with partners.
Happy to answer :)
> What impact has having such clear visibility into your accounts had on your relationship with your wife?
That's a great question. Thankfully when it comes to finances we are very aligned in our habits and goals. So we find it very natural to be open because we know that we're both going to be aligned.
Where we differ heavily though is how much we are willing to really getting onto the nitty gritty details. She really likes knowing how our money works but she also has no interest in spending so much time and effort on it.
But that works great because I love this stuff. So every month or so we have a "finances session" where I sit down with her, take her through the books and make sure we're both happy with everything.
Obviously this very much depends on the couple whether this works but it has for us so far!
I love that, thank you for sharing.
Would you consider a follow up blog post about how you structure and approach your monthly finance sessions? I understand that it would be well outside of your topics of software engineering, performance and open-source, but I find that the human component of our industry is often missing. An insight into how someone has successfully navigated that would be a wonderful read.
Can somebody explain to me the advantage of double-entry bookkeeping? Is it basically just a "checksum" so it's easier to notice when something is off?
Double-entry accounting models the source and destination of funds. If you keep all of your money in one bank account and neither owe anyone or have anyone that owes you, then double-entry accounting is not necessary because you can record just the one side of every transaction – your bank account is the other side.
However, if you have more than one account or debts, or budgets, then it becomes useful to track both sides of a transaction. If you track both sides of a transaction then you can easily answer questions like: 1. how much money do I have in my investment account? 2. how much debt do I have? 3. how much did I spend on recreational social activities?
You can track debts and investments separately, but then you are still making two entries just in two places.
I think many people have few enough debts and investment account that they track these separately, and the third question, budgeting, can be simplified if each vendor is only ever considered for a single budget, for example, all your flights are part of your vacation budget, and you don't care to break out a flight to a career related conference.
Here is my explanation for "software people who understand databases". The structure of the explanation will be as follows:
1. The way you'd do accounting in a database is with two tables: One table for accounts (e.g. your checking account, or the supermarket account, which you don't own) and another table for transactions. The transactions move an amount of money from one account to another, e.g. from your checking account to the supermarket account. Or if you use it for budgeting, you might split your checking account into a groceries account, a rent account etc. (think "categories").2. For performance, you would create indices based on the accounts in the transaction table, so you could easily check what's going on e.g. in your groceries account or how much you spent at the supermarket.
3. Double entry accounting was formalized in the 15th century, way before computers became a thing, but bound paper books were already somewhat affordable. The way you'd do accounting is like this: During the business day, you would write down your transactions as they happen, into a scrapbook, similar to the transactions table mentioned above. At the end of the day, you'd do the "double entry" part, which means you take your "index" books where each book is about one account and you transcribe each transaction from your scrap book into the two books of the two accounts that are mentioned in the transaction, e.g. if you spent $10 from your groceries account into the supermarket account, you'd double enter that transaction both into your "groceries" book and into your "supermarket" book. Then, when you want to check on how much you spent at the supermarket in a particular month, you could easily look it up in the supermarket book (this would be very tedious when using the scrap book). These account centered books are like the indices in the database mentioned above.
So the double entry part is about clever index building for making it easier and faster to understand what's going on in your accounting system.
How are investments modeled in this system? e.g I buy $100 of an index fund which can fluctuate in value.
Not an accountant, so if I get it wrong someone please correct me. But index fund shares are an asset: something you own. So is your car, your house (if you own it), and your computer. When you buy an asset, you paid a certain price for it. When you sell it, you pay a different price. Until you sell it, though, you don't actually have the money, so it hardly matters what its value is until you sell it. If you buy $100 of an index fund and a year later it has grown by 10%, you don't actually have $110 yet until you sell it. So you just track that you have a certain number of shares of the fund. Let's say each share sells for exactly $20 when you bought them, so you have exactly 5 shares. Later the share price is $22, but you don't have $110 yet, you still have exactly 5 shares. When you sell them, then you'll have $110.
So you record two entries:
January 1st, 2025:
January 1st, 2026: At this point you have "realized" ("made real") $10 of profit from this asset. You bought it for $100 and sold it for $110, so the IRS wants you to pay taxes on the $10 profit you made. (This is capital gains tax). Until you sold them, some people would consider you to have $10 profit in "unrealized capital gains", but you did not actually have that profit until you sold the shares. This is important to remember, because if you start counting on that $10 profit but then the share price drops because the economy took a hit, suddenly you don't have $110 worth of shares, you have $90 worth of shares, and you'll make a loss if you sell them now. (This is one of the reasons why only the economically illiterate would propose a tax on "unrealized capital gains": that means taxing people for income they have not actually received, but merely could theoretically receive. Which is both immoral and stupid.)Hope this explanation helps a little. And as I said, if I got something wrong, please correct me and explain how I was wrong; I'm not an accountant. I understand the basic principles, but it's entirely possible I was off on some detail or other.
Accounts (in the accounting sense) are unitless, and refer to whatever meaning we ascribe to them, so we can transfer value from $ to shares, or USD to GBP or whatever.
Lalit describes this I think really well in his article
https://lalitm.com/post/one-number-i-trust/#chapter-4-invest...
Yes, it makes it both really simple to spot mistakes and also allows you to easily audit the whole thing after the fact. In corporate contexts it's a straightforward way to make sure your bookies are also honest, just have an external firm look through the whole thing every now and then.
I must have read half a dozen intro-to-accounting books, and it never ever clicked for me. I understood the concepts, the benefits, but it just felt 'wrong'.
It wasn't wrong of course, there is so much history, ingenuity and the invention of double entry accounting, but I just couldn't get my brain to understand it.
The way the concepts settled in my head was: double entry accounting is just an excellent way of modelling a graph with nodes and edges. Accounts are nodes, transfers are edges. Every edge has a source and a destination.
For a paper ledger, each column is graph node, and each row is a graph edge.
That was enough for me to be able to learn the rest of the things I needed for interacting with the accounting world.
But I also realised that that description really only helps a very small part of the population. :D It makes things so much worse for most people.
"Hey could you help me understanding this accounting thing?"
"Sure, but first thing is, let's learn graph theory! You know who Dijkstra right?"
Whole buckets of nope.
But thats a digression from your actual question - whats the point?
It presents a rigid set of rules of recording transfers, everything has to have a from account and to account (i.e. a graph edge), every row must add up to zero.
Because of that, it makes it easy to spot any mistakes in data entry. If any of your rows dont add up to zero - then you've made a mistake.
It's not really a checksum. It can sometimes function as one (everything should sum to zero, if it doesn't then you have a math error), but since most records you make will just have two entries (spent $25 on groceries, remove $25 from checking account) the everything-sums-to-zero feature isn't going to catch math mistakes most of the time, because there is no math to be done on most entries. Rather, the fact that everything sums to zero helps you track things later on.
To explain that, I'll rephrase, in my own words, the restaurant example from the article, because that was a good example of the concept. Let's say you went to a restaurant with two friends and decided to split the $90 bill three ways, but your friends didn't have $30 in cash on them at the time. You put the whole $90 on your credit card, and your friends paid you back $30 each the next week: one on Monday, and one on Wednesday.
In single-entry accounting you might have written the following transactions:
Thing is, there's nothing to link those transactions together. If you look at these entries three years later, you'll probably be left scratching your head as to why Alice paid you back $30: there's no $30 transaction, so the $90 restaurant transaction won't jump out at you as the reason why Alice paid you back.But with double-entry bookkeeping, you'd write that as follows:
Thursday Jan 1st:
Monday Jan 5th: Wednesday Jan 7th: It's not always obvious when you're new to double-entry accounting which entries should be positive or negative, but if you remember the "must add to zero" rule you'll be more likely to get it right. Money flowing into an account is positive, money flowing out of an account is negative. For credit cards, the money flows "out of" your credit card and into the restaurant's ownership, so the sign should be negative. When you pay the credit card bill later, the sign will be positive on the credit card account (and negative on your checking account, thus again adding to zero) because money is flowing out of your checking account and into your credit card account.Now, look at that double-entry accounting. When you look at the Wednesday Jan 5th entry, and you see that Alice paid you back $30, you'll start searching for a $30 transaction earlier, and you'll pretty quickly find the January 1st and figure out that she owed you $30 because you had paid her share of the restaurant bill on the 1st. And even if the amounts don't line up (let's say she paid you $20 on Jan 5th and $10 on Jan 12th), there's still a "money Alice owes me" category which has a +$30 entry on the 1st, then -$20 on the 5th and -$10 on the 12th, all of which makes it pretty easy to figure out what Alice is paying you back for.
So by recording each entry in at least two places (it's not always exactly two places, e.g. the January 1st expense is recorded in four places total), you get more linkage between the items and it becomes a lot easier to see why the money was going out or coming in.