Most personal budgeting advice seems to be close but not exact.

Budgeting tends to be monthly. Transactions are often bi-weekly, every 30 days, every three months. If paid bi-weekly, some months have three pay days. Income and expenses occur throughout the month.

A credit-card purchase is money spent today but paid a month later (assuming paid in full).

I want an exact to-the-day, to-the-penny budget and forecast.

Rather than throwing an extra $50 toward a loan repayment, how much extra can I afford to pay (to the penny)?

The budget would have these requirements:

  • Daily to-the-penny projected balance of each account
  • Pay bills and debts never letting my bank balance drop below $750
  • Make extra payments with all available money
  • How much money to-the-penny can I afford to spend today?

What software do you recommend to achieve this? Most software I've tried falls short in one of these areas (especially locking budgets into monthly only).

  • 6
    To-the-day to-the-penny forecasting assumes that you can predict to-the-penny and to-the-day what your expenses will be. You can't possibly predict to the penny how much you will need to spend to fill your car with gas next week. And if you can't predict it then no piece of software can. – DJClayworth May 3 '12 at 14:40

I've tried Mint, and I've tried Quicken. Now, I think Quicken is an annoying, crashy little piece of software, but it is also quite capable; overall I think it has the features you want. You can enter your bills, broken down by category, in advance. You can enter your paychecks, broken down by category (gross income, federal income tax, state income tax, social security, SDI, transfers to tax-protected 401(k) account, etc) in advance. You can enter in your stock trades and it can tell you how much you'll need to end up paying in capital gains taxes. You can even enter in your stock option vesting schedule in advance (it's a royal pain because you can't go back and change anything without deleting everything, but you can do it). It'll forecast your bank account balance in all of your bank accounts in advance with a shiny chart. It'll even model your loans, if you set it up right.

I didn't do too much with the "budgeting" tools per se, but the account-balances-daily features sound like the closest thing to what you're looking for that's likely to exist.

The only thing that's a trifle tricky is that transfers from one account to another may take multiple days (hello, ACH) and you'll have to decide whether to record them at departure or arrival.

  • +1 - I use Quicken, but I don't use it as much as fennec does. I don't have any problems with crashing, but I read quite a bit about it. It seems to be a gamble if the software works for you or not. But the features are there. – MrChrister May 3 '12 at 15:34
  • Thanks, fennec. I'll try Quicken. They have a 60-day return policy. If it doesn't work, I'll return it and try another (or create my own in Excel or something). – Steven May 3 '12 at 17:01

I really don't know about will it help you, but here is what I do:

  1. Write all calculations I need in Numeric Notes (http://itunes.apple.com/kz/app/numeric-notes/id464069442?l=ru&ls=1&mt=12)
  2. If I need to see how it should affect future, just select needed calculations, paste it somewhere, and made modifications.

It is not classic solution, but maybe it will work for you (works for me very well).

  • Thanks for the suggestion JamesK. If Quicken doesn't do the trick for me, I'll look into Numeric Notes (or a Windows equivalent). – Steven May 3 '12 at 17:02

I wrote a little program one time to try to do this. I think I wrote it in Python or something. The idea was to have a list of "projected expenses" where each one would have things like the amount, the date of the next transaction, the frequency of the transaction, and so on. The program would then simulate time, determining when the next transaction would be, updating balances, and so on. You can actually do a very similar thing with a spreadsheet where you basically have a list of expenses that you manually paste in for each month in advance. Simply keep a running balance of each row, and make sure you don't forget any transactions that should be happening.

This works great for fixed expenses, or expenses that you know how much they are going to be for the next month. If you don't know, you can estimate, for instance you can make an educated guess at how much your electric bill will be the next month (if you haven't gotten the bill yet) and you can estimate how much you will spend on fuel based on reviewing previous months and some idea of whether your usage will differ in the next month. For variable expenses I would always err on the side of a larger amount than I expected to spend. It isn't going to be possible to budget to the exact penny unless you lead a very simple life, but the extra you allocate is important to cushion unexpected and unavoidable overruns.

Once you have this done for expenses against your bank account, you can see what your "low water mark" is for the month, or whatever time period you project out to. If this is above your minimum, then you can see how much you can safely allocate to, e.g. paying off debt. Throwing a credit card into the mix can make things a bit more predictable in the current month, especially for unpredictable amounts, but it is a bit more complicated as now you have a second account that you have to track that has to get deducted from your first account when it becomes due in the following month. I am assuming a typical card where you have something like a 25 day grace period to pay without interest along with up to 30 days after the expense before the grace period starts, depending on the relationship between your cut-off date and when the actual expense occurs.

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