How much should you tip? That depends on quality of service as well as whether you are at a sit-down restaurant or a place of less-than-full service. Here are guidelines for calculating 5%, 10%, 15%, and 20%.

Notes about rounding:

  • To calculate any percentage of your check, round off the amount to the nearest dollar: Round up if the cents are more than 50; round down if less. If the cents are less than 50 and you feel guilty about not tipping on the cents, then round up just so you feel better.
  • If your check is over $100, you may want to round off to the nearest $10, to make your calculation easier. If you’re OK with even more approximating, you may want to round off even a number less than $100 to the nearest $10. For example, for $37.23, you might use $40 for your calculation.

To calculate 10%:

10% is 0.1. To multiply by 0.1, slip the decimal point one place to the left: 10% of $37.00 = $3.70. So a tip of 10% on a $37.23 check is about $3.70.

To calculate 5%:

Find 10%. See 10% calculation above. That’s $3.70.

Divide that in half. 5% of $3.70 = $3.70/2 = $1.85. So a 5% tip on a $37.23 check is about $1.85.

To calculate 20%:

Find 10%. See 10% calculation above.

20% is twice 10%, so double the 10% amount: 2*$3.70 = $7.40. So a 20% tip on a $37.23 check is about $7.40.

To calculate 15%. This is probably the hardest one to do in your head. If you’re at a place with paper napkins, one may be convenient just now.

Calculate 10%. (See above.) That’s $3.70.

Calculate 5%. That’s half of 10%, so divide your 10% result in half. $3.70/2=$1.85.

At this point, if you feel you have too many digits. You may want to round off. Round $1.85 to $1.90.

10% + 5% = 15%, so combine your 10% and 5% results: $3.70 + $1.90 = $5.60. So a 15% tip on $37 is $5.60.

Alternative way to add $1.90 + $3.70: Notice that $1.90 is 10 cents less than $2.00. Instead of adding $1.90, try adding $2 and subtracting $0.10: $3.70 + $2 = $5.70. $5.70 – $0.10 = $5.60.

This method entails more steps than does just adding $3.70 and $1.90, but the steps are easier, especially once you get used to doing it that way.