A tip is a percentage of the bill, so a 20% tip on $80 is $80 × 0.20 = $16. The questions that make tipping awkward are the details: whether to tip on the amount before or after tax, how to split the total fairly, and what percentage is customary. This tip calculator handles all three. It shows the tip and total, each person's share, and a comparison table of common percentages so you can choose.
The Emily Post Institute's general tipping guide suggests 15–20% of the pre-tax bill for sit-down restaurant service. That is a social convention rather than a rule, and practice varies by country, region and type of service.
How to use the tip calculator
- Enter the bill total as printed.
- If you want to tip on the pre-tax amount, enter the tax shown on the receipt and choose "Amount before tax".
- Enter the tip percentage. The comparison table shows 10% to 25% at a glance.
- Enter how many people are splitting the bill, and choose whether to round each share up to the next dollar.
Formula
Worked example
Three friends have a bill of $86.40, which includes $6.40 tax, and want to leave 20% of the pre-tax amount.
- Pre-tax amount: $86.40 − $6.40 = $80.00.
- Tip: $80.00 × 0.20 = $16.00.
- Total: $86.40 + $16.00 = $102.40.
- Per person: $102.40 ÷ 3 = $34.13 (rounded up to the dollar, $35 each, or $105 total).
Customary tips by service (US)
These ranges are from the Emily Post Institute's general tipping guide. They are etiquette guidance, not law, and local customs differ.
| Service | Suggested tip |
|---|---|
| Sit-down restaurant | 15–20% of the pre-tax bill |
| Buffet | 10% of the pre-tax bill |
| Takeout | No obligation; 10% for extra service or a large order |
| Food delivery | 10–15% of the bill; $2–5 for pizza depending on order size |
| Bartender | $1–2 per drink |
| Hair salon, manicure, spa | 15–20% |
| Taxi | 15–20% of the fare |
Quick mental math for tips
Move the decimal point one place left to get 10%: on $64.00, 10% is $6.40. Double it for 20% ($12.80). For 15%, add half of the 10% figure ($6.40 + $3.20 = $9.60). For 18%, take 20% and subtract 2% (one fifth of 10%): $12.80 − $1.28 = $11.52.
When splitting unevenly, for example one person had a much larger meal, calculate each person's share of the pre-tax subtotal first, then apply the same tip percentage and their share of the tax. The percentage calculator can work out each share's percentage of the bill.
Caveats and assumptions
- Many restaurants add an automatic service charge for large groups. Check the bill so you don’t tip twice.
- Tipping customs differ outside the US; in many countries service is included in the price.
- Rounding each share up means the group leaves slightly more than the chosen percentage.
- Amounts are rounded to the cent.
Frequently asked questions
How much is a 20% tip?
Multiply the bill by 0.20. On $80 that is $16. A quick method is to find 10% by moving the decimal point one place left and doubling it.
Should I tip on the total before or after tax?
The Emily Post Institute’s guide bases restaurant tips on the pre-tax bill. Many people tip on the full total for simplicity, which adds a little to the tip.
What is a normal tip at a restaurant in the US?
The Emily Post Institute suggests 15–20% of the pre-tax bill for sit-down service.
How do I split a bill with tip?
Add the tip to the bill and divide the total by the number of people. Use the per-person line above, with rounding up if you prefer whole dollars.
How do I calculate 15% tip quickly?
Find 10% by moving the decimal point one place left, then add half of that. On $42: $4.20 + $2.10 = $6.30.
Sources
- The Emily Post Institute — General Tipping Guide — customary tip ranges by service
- OpenStax Prealgebra 2e — 6.2 Solve General Applications of Percent — percent of an amount
- IRS — Tip Recordkeeping and Reporting — how tips are treated for workers and employers
This calculator gives estimates for planning and education. Check measurements, local codes, supplier specs and your school's official policy before relying on a result. See our disclaimer and how we build and check calculators.