How to Calculate a Tip Percentage on a Restaurant Bill
Short answer
Tip = bill × tip% ÷ 100. On an 85.50 bill, 18% is 85.50 × 0.18 = 15.39; total ≈ 100.89. In the US, 15–20% is common for table service.
Figuring a tip at the table should take seconds. Move the decimal point or use a percentage. Our tip calculator also splits the bill between friends.
Quick mental math
- 10%: move the decimal one place left (85.50 → 8.55).
- 20%: double the 10% amount (17.10).
- 15%: 10% plus half of that (8.55 + 4.28 ≈ 12.83).
- 18%: 20% minus a little, or bill × 0.18.
Worked example
Bill 85.50, tip 18%, two people. Tip = 15.39. Grand total = 100.89. Each person pays about 50.45. Tick “round up” in the tip calculator if you prefer whole numbers.
Before tax or after tax?
Customs differ. Many people tip on the pre-tax subtotal; others tip on the total on the receipt. Decide as a group and stay consistent. To separate tax from a total, use the sales tax calculator in “remove tax” mode.
US vs UK tipping norms
In the US, 15–20% for sit-down service is typical when no service charge is included. In the UK, a discretionary 10–12.5% is common if service is not already added — check the bill for a service charge first.
Percentage practice
Tips are everyday percentages. For more formulas, see percentage increase and the percentage calculator.
Related reading: how to calculate sales tax.
Related reading: how to calculate discount percentage.
Related reading: a levels exam guide.
More worked numbers
Change one input at a time so you build intuition. Write the formula, substitute values, then confirm with the free tip calculator. If the tool disagrees with your hand math, check units first (months vs years, percent vs decimal, inclusive ranges).
Common mistakes to avoid
- Mixing up percent and decimal forms (15% is 0.15, not 15).
- Using the wrong base when calculating a change or a reverse percentage.
- Ignoring fees, tax or daylight saving when the real-world total depends on them.
- Rounding too early in multi-step arithmetic.
How to practise
Invent three mini-problems from your own life — a bill, a grade, a trip, a loan quote — and solve them on paper before you open the calculator. Teaching the steps to someone else is one of the fastest ways to lock in the method.
Related tools on ViralScopeHub
After you finish this guide, explore the linked tools above and the related articles for neighbouring skills. Our calculators run privately in your browser with no sign-up, so you can check homework, budgets or work estimates without uploading data.
Quick reference card
Keep the short answer box at the top of this page as your cheat sheet. When a search result brought you here for a specific phrase, that box is designed to match the query with the formula first, then the examples below fill in the judgement calls.
Frequently asked questions
How do I calculate an 18% tip?
Multiply the bill by 0.18, or take 20% and subtract a tenth of that 20%. Double-check units and confirm with the linked tool on this page before you rely on the figure for money or school decisions.
Should I tip on tax?
Either is acceptable; many tip on the pre-tax amount. Agree with your group. Double-check units and confirm with the linked tool on this page before you rely on the figure for money or school decisions.
How do I split a tip evenly?
Add tip to the bill, then divide by the number of people — or use our tip calculator. Double-check units and confirm with the linked tool on this page before you rely on the figure for money or school decisions.
What if service is already included?
Do not double-tip unless you want to. Read the receipt for a service charge. Double-check units and confirm with the linked tool on this page before you rely on the figure for money or school decisions.