Mastodawn

Julia Evans Apr 13, 2023

today I'm thinking about the "don't use floating point for money" advice I hear all the time. It obviously has a lot of truth to it.

But -- Excel/Google Sheets uses floating point for all of its calculations, people use spreadsheets for money calculations all the time, and it generally seems to work just fine -- the results get rounded for display.

So I'm trying to figure out if there's a more nuanced guideline than "never use floating point for money".

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@b0rk I guess the important thing to remember is that errors (can) compound, so floating point is fine if you're not doing any complex or repeated calculations.

Time-limited budgets is probably fine, but holding accounts and calculating compounding interest and stuff, nah, just move to counting cents/cent fractions in an integer or something.