Tip before or after tax?
Short answer: tip on the pre-tax subtotal. Longer answer: the difference is a rounding error, so do not lose sleep at the table.
Last checked September 2026
Custom is to calculate the tip on the pre-tax food and drink, because the tax is money the government takes, not service the server gave. But sales tax is a few percent, so tipping on the grand total instead costs you cents on most checks. Use whichever is easier and round to a clean number.
Why pre-tax is the etiquette answer
A tip is a percentage of the service. Sales tax is not service, so the traditional rule is to apply your percentage to the subtotal before tax. Most etiquette guides land here.
Why it barely matters
Sales tax in the US runs from zero to about 10% depending on the state. Twenty percent of that tax line is a very small number.
- Pre-tax tip: 20% of $100 is $20.00.
- Post-tax tip: 20% of $108 is $21.60.
- The difference is $1.60 on a $100 check.
When to just use the total
If you only have the grand total in front of you, or the card reader suggests tips off the total, take the easy path. Nobody is auditing whether you backed out the tax. What matters more is not tipping on top of an auto-gratuity that is already on the bill.
Do the math for your check
The restaurant tip calculator works on the pre-tax figure and reprints your number. For the raw amounts at each rate, see the tip percentage chart.
This is US customary guidance, not tax or legal advice. If a business posts its own policy, that policy wins.