Tip Calculator

What is a tip calculator?

A tip calculator takes a bill amount and a tip percentage and works out three numbers: the tip itself, the total you're paying, and, if more than one person is covering it, exactly what each person owes. Type in the bill, pick a percentage, and the arithmetic is done for you instead of on a napkin or a phone's basic calculator app.

This one adds two things a plain calculator app can't: a fair way to split a bill that doesn't divide evenly between everyone, and the option to tip on the amount before sales tax was added rather than after.

How to use it

1. Enter the bill: type in the bill amount, then choose a tip percentage from the 10, 15, 18, 20 or 25 percent buttons, or type any other figure into the box next to them.
2. Set up the split: enter how many people are splitting the bill, and if you'd rather tip on the pre-tax amount, switch that toggle on and enter the sales tax percentage.
3. Read off the results: the tip, the total, and what each person owes appear immediately, with the copy button ready to grab the full breakdown.

Splitting the bill when it doesn't divide evenly

The percentage is the easy part. The split is where things break: a 100 bill divided three ways is 33.333... each, and nobody can hand over a third of a cent. Most calculators round each share to 33.33 and stop there, which means three people paying their share only cover 99.99 between them, a cent short of the bill.

This calculator hands out the leftover cents one at a time instead, so the shares always add back up to the total exactly, and it tells you which person pays the extra cent. Take an 18% tip on a 100 bill: the tip is 18, the total is 118, and split three ways that comes to 39.34, 39.33 and 39.33 — which adds back to exactly 118.00.

That property isn't a spot check. It was verified against every bill total from 0 to 200.00 paired with every party size from 1 to 40 people, 800,040 combinations in all, and in every one of them the shares sum to the total exactly and no two people's shares differ by more than a cent.

Tipping before or after tax

Tipping on the subtotal before sales tax was added, rather than on the full bill, is a real and widely held convention, on the reasoning that sales tax isn't the restaurant's money and shouldn't factor into the tip. This calculator supports both: leave the toggle off to tip on the full bill, or switch it on and enter the sales tax rate to tip on the subtotal instead.

The difference is bigger than it sounds. Take a 100 bill that already includes 8.875% sales tax, the New York City rate, tipped at 20%. Tip on the full bill and it's 20.00. Tip on the pre-tax subtotal and it's 18.37.

Getting that subtotal back out is a reverse percentage: the bill divided by 1 plus the tax rate, not the bill with the tax percentage simply subtracted off, which is a common but different calculation and gives the wrong subtotal. All the arithmetic here, tax, tip and split alike, is worked in exact fractions and rounded only once at the end, so nothing drifts along the way.

One honest limitation: tipping customs vary enormously from country to country, and this tool takes no view on what you should tip. It only does the arithmetic on whatever percentage you give it. There's no currency setting either, because the maths is identical no matter what units you're typing.

Why is it free?

The whole calculation runs in your browser. Nothing you type is uploaded anywhere, there's no account to create, and nothing is stored, so it's free to use with no watermark on the result.