A Tip Calculator

A tip is just a percentage of a bill, yet most of the arguments around it come from two decisions rather than from arithmetic: what you take the percentage of, and at what point you split it.

Bill amountThe figure you are tipping on. Decide whether that is before or after tax and stay consistent.Tip percentage(%)18 per cent is a common mid-range choice where tipping is expected.Number of people splittingEnter 1 if you are paying alone.

Tip

15.39

Total including tip: 100.89
Tip per person: 7.695
Total per person: 50.445

Values update as you type. This calculator covers the single scenario its formula assumes — see Common Mistakes for what it leaves out.

The formula this calculator uses

Tip = bill x rate; total = bill x (1 + rate)

bill: The amount you are tipping on — decide once whether it is before or after tax
rate: Tip percentage written as a decimal, so 18 per cent becomes 0.18
tip: The gratuity itself, equal to bill x rate
total: Bill plus tip, which is what actually leaves your account

How to check the result by hand

1
Choose the base and stay with it
Decide whether the percentage applies to the pre-tax subtotal or the tax-inclusive total. On a bill carrying 9.50 of tax the two bases differ by 1.71 at eighteen per cent. Whichever you pick, apply it consistently to every bill in the same setting.
2
Turn the percentage into a decimal
Eighteen per cent is 0.18, twenty per cent is 0.20, fifteen per cent is 0.15. The division by a hundred is the step people skip when working quickly, and skipping it inflates the tip by a factor of a hundred.
3
Multiply the bill by the rate
85.50 x 0.18 = 15.39. This single multiplication is the whole of the tip calculation; everything else is bookkeeping around it. Check the magnitude first, because a tip near a fifth of the bill should look like roughly a fifth of the bill.
4
Add the tip to the bill
85.50 + 15.39 = 100.89. The total is what actually leaves the account, and it is the figure to compare against the slip. If the two disagree, the tip or the rate was mistyped rather than the addition.
5
Divide the tip-inclusive total by the number of people
100.89 / 2 = 50.445, of which 7.695 is tip. Dividing after the tip is added keeps each person's share proportional to the whole; dividing first and tipping separately is what dilutes the rate.

For worked examples, common mistakes and the limits of this formula, read the full How To Calculate A Tip page.