How to calculate a tip without an app
The formula is short: tip = bill × tip% ÷ 100, and total = bill + tip. Or do it in one step: total = bill × (1 + tip% ÷ 100). An 18% tip on 64 is 64 × 0.18 = 11.52, for a total of 75.52.
Mental math for common rates
- 10%: move the decimal one place left. 10% of 64 is 6.40.
- 20%: double the 10%. 6.40 × 2 = 12.80.
- 15%: 10% plus half of that. 6.40 + 3.20 = 9.60.
- 18%: 20% minus 2% (2% is a fifth of 10%). 12.80 − 1.28 = 11.52.
- 25%: divide by four. 64 ÷ 4 = 16.
Rounding the bill first makes this easier. On 47.80, think 48: 20% is about 9.60.
Before tax or after tax?
Etiquette guides in the US commonly suggest tipping on the pre-tax amount, though many people tip on the total for simplicity, and the difference is small. On a 60 bill with 8% tax (64.80 total), 20% is 12.00 on the pre-tax amount or 12.96 on the total. Card terminals usually calculate on the total including tax, so check which number the suggested tip buttons use.
Splitting the bill
Work out the total with tip first, then divide. A 138 bill with 20% tip is 165.60; split four ways that is 41.40 each. If people ordered very different amounts, multiply each person's own share by the same tip rate instead.
Is a service charge already included?
Read the bill before adding a tip. Many restaurants add an automatic gratuity for large groups, and in much of Europe and Asia a service charge is often included in the price or listed as a line on the bill. Tipping customs vary a lot by country: in the US, 15–20% at sit-down restaurants is the common expectation, while in Japan tipping is generally not expected. When you travel, check a current local guide rather than applying your home habits.
Other places you might tip
The same formula works for delivery, taxis and ride-hailing, salons, and hotel services. For small amounts, people often round up to a whole number instead of using an exact rate.
Doing it with PercentSnap
- Open the calculator and pick Tip.
- Enter the bill and the tip percentage.
- You get the tip and the total. Copy the result, or look back at earlier calculations in the history list, which stays in your browser.
It works in any phone or desktop browser with nothing to install, and every mode is free.