Splitting & Fairness
The part of this that does have a right answer
Most of this site is judgment with sources under it. This category is not. Dividing a restaurant bill, a group present or a weekend rental has an arithmetically correct answer, and the only reason it goes wrong is that nobody wants to be the person with the calculator out.
These tools are that person, so you do not have to be. They show the split line by line, including the awkward parts — who ordered the wine, who is on a different budget, who paid the deposit four months ago — in a form you can screenshot into the group chat and let stand on its own.
Splitting a group gift when you are not all equally close to the person. A fair share each, instead of the total divided by however many of you there are — and the $10 federal ceiling on an office collection for your own boss.
Open tool →Bill Split CalculatorSplits a restaurant check between people who did not order the same thing — to the cent, under a rule you pick and we admit is ours. The tip comes off the bill before tax, which is what Emily Post actually says and what almost every other splitter quietly gets wrong.
Open tool →Rent Split CalculatorSplits rent between roommates whose bedrooms are not the same. Everyone says what each room is worth to them, and the tool hands back a room and a price for each person that nobody would want to swap. It is the one calculator here with a mathematical proof behind it rather than a range, and it shows the check rather than just claiming it.
Open tool →