How it's calculated
tip = base × tip% ; per person = (bill + tip) ÷ people
bill = total bill, base = bill (or bill − tax if tipping pre-tax), tip% = tip rate, people = number splitting the bill.
Common questions
Should I tip on the pre-tax or post-tax amount?
Either is common, but tipping on the pre-tax subtotal is the more traditional approach. This tool lets you pick.
What is a standard tip in the US?
For sit-down service, 15 to 20 percent is typical, with 18 percent a common middle ground for good service.