How to Calculate a Tip in Your Head

To find 10% of any bill, move the decimal point one place to the left.

Every other tip percent is built from this one number by doubling it, halving it, or adding and subtracting small pieces.

For 18% you can also round up to 20% and leave a little more, which many people do anyway.

Awkward totals get easier if you round to the nearest dollar before you start. A $47.80 bill is about $48:

The exact 20% would be $9.56, so rounding the bill up first gives a tip that is a few cents generous rather than short.

Even split: add the tip to the bill, then divide by the number of people. A $96 bill with a 20% tip is $96 + $19.20 = $115.20, so 4 people pay $28.80 each.

Uneven orders: each person tips on their own share. If you ordered $30 of a $96 bill, your 20% tip is $6, and you pay $36.

When the total doesn't divide evenly, round each share up to the next cent. The group pays a few cents extra instead of leaving the bill short.

• Coupons and discounts: many people tip on the price before the discount, because the service was the same. A $60 meal with a $15-off coupon would get a 20% tip of $12, not $9.
• Tax: etiquette guides often suggest tipping on the amount before tax. The difference is small: on $6.40 of tax, a 20% tip changes by $1.28.
• Service charges: some bills, especially for large groups, already include a service charge or "gratuity". Check the bill before adding a tip so you don't tip twice.

Customs vary by country and type of service, so these are common practices rather than rules.

Try each one in your head, then open the answer.

1. What is a 15% tip on $52?
   Show answer

   5.20 + 2.60 = $7.80
2. What is a 20% tip on $37.50?
   Show answer

   3.75 × 2 = $7.50
3. What is an 18% tip on $85?
   Show answer

   20% is 17.00, 2% is 1.70, so $15.30
4. 4 people share a $96 bill and leave a 20% tip. How much does each pay?
   Show answer

   96 × 1.2 = 115.20, and 115.20 ÷ 4 = $28.80
5. You paid $70 on a $58 bill. What percent did you tip?
   Show answer

   12 ÷ 58 × 100 ≈ 20.69%
6. A $60 meal had a $15-off coupon. What is a 20% tip on the original price?
   Show answer

   10% of $60 is $6, so $12