loot.toolsType in the bill amount and choose how much to tip, either from the common presets or your own percentage. The calculator shows the tip on its own, the grand total, and what each person pays once you split it. Turn on rounding to bump the total up to the nearest whole amount so you're not fishing for coins.
In the US, 15 to 20 percent is the usual range for sit-down restaurant service, with 18 percent a safe default and 20 percent or more for service you really liked. Tipping customs vary a lot by country though, so what's standard in one place can be unusual in another. The presets here cover the common range, and you can always enter an exact number.
Set how many people are sharing the bill and the per-person figure updates instantly, tip included. It splits everything evenly, which is the simplest way to handle a group. Everything runs in your browser, so no numbers leave your phone or laptop while you're sorting out who owes what at the table.