how to split a bill and tip
Splitting a restaurant bill looks trivial until the total turns out not to be a clean multiple of the number of people. The hard part is not the tip percentage, it is the leftover cent after the split, and someone always ends up paying a little more or a little less.
11,000 cents divided by 3 gives 3,666 cents each, with 2 cents left over. Since all three decimal fractions tie, the first two people in line get the extra cent and the third ends up 1 cent short.
5,269 cents divided by 4 is 1,317.25 per person; only 1 cent is left over after rounding down, and it goes entirely to whoever has the largest pending fraction.
Rounding every share up to make cash payment easier pushes the amount collected $1.00 past what was actually owed: nobody loses a cent, but the restaurant or server ends up with $1.00 more than the bill asked for.
The tip is applied to the subtotal, the bill amount you type. If the restaurant already added a service charge, type the amount without it and set the tip, or type the total with the charge included and leave the tip at 0%. That keeps you from tipping on top of a tip.
Under the largest remainder method, the person (or people) whose decimal fraction was closest to rounding up to the next cent gets that extra cent. It is not random and it is not always the same person: it depends on how each individual share lands after rounding down, so the next bill can hand that cent to someone else in the group.
In many countries a service charge of around 10 to 15 percent is already printed on the bill and is not legally mandatory, with anything extra being optional. In the United States most restaurants add no service charge at all, and the social norm runs closer to 15 to 20 percent of the pre-tip total, which changes the whole calculation of what each person owes.
An equal split (one share per person) ignores who ordered the pricier entrée or an extra round of drinks. The alternative is weighting shares: instead of everyone counting as "1", whoever consumed more gets a higher weight, and each person's share becomes proportional to that weight over the group's total weight, not a fixed equal fraction.
Yes, slightly: rounding every individual share up adds more than the bill's real total, because every fraction of a cent turns into a full extra cent. For a small group the overage typically lands somewhere between a few cents and a dollar or two in total, usually absorbed as extra tip for the server.
All math runs entirely in your browser. No amount is sent to any server.