How to Calculate a Tip: Formula, Examples and Mental Math

To calculate a tip, multiply the bill by the tip percentage and divide by 100: tip = bill × tip % ÷ 100. On a $48.50 bill, a 20% tip is 48.50 × 20 ÷ 100 = $9.70, so you pay $58.20 in total. If you are splitting the bill, divide that total by the number of people.

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That is the whole method. The rest of this guide covers worked examples, shortcuts for doing it in your head, a quick-reference tip table, and the small decisions that change the number: tax, rounding and uneven shares. If you just want the answer, the free tip calculator does all of it in one step.

The tip formula

Three formulas cover almost every situation:

• Tip = bill × tip % ÷ 100
• Total = bill + tip
• Per person = total ÷ number of people

You can also skip the separate tip step and multiply the bill by 1 plus the tip written as a decimal. For a 20% tip the multiplier is 1.20, so $48.50 × 1.20 = $58.20, the same total as above.

Percent means "per hundred", which is why you divide by 100. So 18% is 18 hundredths, or 0.18. Converting the percentage to a decimal first (15% → 0.15, 18% → 0.18, 20% → 0.20) turns the whole thing into one multiplication. If percentages in general trip you up, the percentage calculator answers any "X% of Y" question.

Worked example: a $48.50 bill

Here is the same $48.50 bill at the three most common rates. Tips are rounded to the nearest cent.

The gap between 15% and 20% on this bill is less than