18% on a bill of 50, split between two
The tip is 50 × 0.18 = 9, so the total is 59 and each person pays 29.50.
Rounding each share to a whole unit would make it 30 each, a total of 60 — the tip rises to 10, or 20%.
Tip calculator
Enter the bill, choose a percentage and the number of people. The tip, the total and each share appear straight away, with the option to round to a clean amount.
Result
Fill in the fields to see your result.
How it works
A tip is a percentage applied to a base amount, and the only real decision is which base. Some people tip on the total printed on the bill; others tip on the amount before tax, on the grounds that a tip rewards service rather than the tax authority. On a bill with 15% tax, the difference between the two is about 13% of the tip itself — small in absolute terms, but worth being deliberate about.
Splitting is where cents get lost. An exact share rarely divides evenly, so this calculator tells you when the individual amounts do not quite add up to the total, and offers two ways to round: to a whole total, or to a whole amount per person. Rounding never takes the total below the bill, so nobody ends up underpaying.
The comparison table shows what the common percentages would give on the same bill. It is often faster to look at that than to change the slider three times.
Formulas used
Tip and total
tip = base × (p ÷ 100) total = bill + tip
- base
- the bill, or the bill before tax
- p
- the tip percentage
Removing tax to find the base
base = bill ÷ (1 + tax ÷ 100)
Divide, never subtract: subtracting the tax percentage from the total takes a percentage of the wrong number.
Worked examples
Tipping on the pre-tax amount
A bill of 115 that includes 15% tax comes from a pre-tax amount of 115 ÷ 1.15 = 100.
A 20% tip on that base is 20, not 23. The total is 135, and the tip measured against the full bill is 17.4%.
Assumptions and limits
- The amount you enter is the bill as printed, with tax included.
- Every amount is rounded to two decimals, as it would be on a receipt.
- Rounding never brings the total below the bill.
- The tip is assumed to be shared according to the establishment’s own rules; this calculator does not model tip pooling.
Frequently asked questions
How much should I tip?
It depends entirely on where you are. In the United States and Canada, 15–20% in a sit-down restaurant is the usual range, and staff wages assume it. In much of Europe service is included and rounding up is enough. In Japan, tipping can cause genuine awkwardness.
This calculator does the arithmetic; it deliberately does not tell you what is polite, because that answer is local.
Should I tip on the pre-tax or the post-tax amount?
Both are common and neither is wrong. Tipping before tax is the stricter reading — a tip rewards service, and tax is not service. Tipping on the total is simpler and slightly more generous. Pick one and be consistent.
Why does rounding change the tip percentage?
Because rounding adjusts the total, and the tip is whatever is left after the bill. The calculator shows the percentage actually applied after rounding, so you can see how far it moved from what you asked for.
The shares do not add up to the total. Why?
A total that does not divide evenly leaves a remainder of a cent or two. There is no arithmetic fix — someone pays one cent more. Rounding each share to a whole unit avoids the problem entirely.
Updated
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