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Well, how much money can you save by efficient rounding? Surely not that much that anyone would bother. There's a thing called "Kaufmännisches Runden", which is

Well, how much money can you save by efficient rounding? Surely not that much that anyone would bother. There's a thing called "Kaufmännisches Runden", which is kind of cheating as well. > But yes, rounding does happen a lot – what's important is that everybody uses the same, transparent rules for that, or it becomes impossible to double-check somebody's books, tax declaration, invoice etc. They don't, that's why it doesn't matter that much ;)

lxgr 3y ago
> Well, how much money can you save by efficient rounding? You and me? Probably a few cents. A bank or a large corporation selling things billed in sub-cent amounts? Single-digit percentages of their gross revenue, i.e. many millions. Just as a very simple example: I'm your bank/phone provider/..., and I'm charging you a flat fee of 1.9 cents per transaction/call/... You're my customer and make a billion of such transactions per year. Option 1: 1000000000 * 0.019 = 19000, you owe me $19000000. Option 2: There are no fractional cents, so let's just round up each individual billing event. 1000000000 * 0.02 = 20000000, you owe me $20000000. Cool, a free extra million for the company! This is why these things are precisely regulated when it comes to sales tax/VAT, for example. > There's a thing called "Kaufmännisches Runden", which is kind of cheating as well. Always depends on which side you're on. If you're getting a refund, it can work in your favor! Importantly, it's a precisely defined rule so that it's not possible to cheat in the implementation.