Guide · Dining out
Tip Percentage — How to Calculate & Split a Tip
Updated: June 2026
Working out a tip is just finding a percentage of the bill — but doing it quickly at the table, and splitting it fairly between friends, takes a couple of reliable tricks. This guide covers the standard tip percentages, the fastest mental shortcuts for 15%, 18% and 20%, how to divide a tipped bill, and the long-running pre-tax versus post-tax question.
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The tip formula
A tip is a percentage of the bill, and the total is the bill plus the tip:
total = bill × (1 + percent ÷ 100)
On a 45 bill at 20%: the tip is 45 × 0.20 = 9 and the total is 45 × 1.20 = 54. The multiplier version gets you straight to what you'll pay; the first gets you the gratuity to write on the slip.
The 10% trick
Every quick tip starts from 10%, which you get by moving the decimal one place to the left. From there:
- 15% — 10% plus half of it again. On 60: 6 + 3 = 9.
- 18% — almost double 10%, nudged down a touch. On 60: roughly 11.
- 20% — just double the 10%. On 60: 6 × 2 = 12.
These three cover nearly every situation, and all you ever have to compute precisely is that first 10%.
Common tips at a glance
| Bill | 15% | 18% | 20% |
|---|---|---|---|
| 20 | 3.00 | 3.60 | 4.00 |
| 40 | 6.00 | 7.20 | 8.00 |
| 60 | 9.00 | 10.80 | 12.00 |
| 100 | 15.00 | 18.00 | 20.00 |
Splitting the bill
To split a tipped bill evenly, add the tip first, then divide by the number of people: total ÷ people. A 60 bill with a 20% tip is 72; split four ways that's 18 each. If you'd rather everyone tip on their own share, divide the bill first and apply the percentage per person — the grand total comes out the same, so it's purely a matter of convenience.
Pre-tax or post-tax?
Strictly, a tip rewards service, not tax, so etiquette leans toward tipping on the pre-tax subtotal. In practice many people tip on the full total because it's the bigger, more visible number — and it's marginally more generous. Either is socially fine; the difference on a typical bill is small. If you want to be precise, take the percentage of the subtotal shown above the tax line.
Frequently asked questions
How do I calculate a 20% tip?
Find 10% by moving the decimal one place left, then double it. On a 45 bill, 10% is 4.50, so 20% is 9.
How do I split a bill with tip between people?
Add the tip to the bill, then divide by the number of people. A 60 bill with a 20% tip is 72, split four ways is 18 each.
Should I tip on the pre-tax or post-tax amount?
Etiquette favours the pre-tax subtotal, since the tax isn't part of the service. Tipping on the total is common too and slightly more generous.
What's a standard tip percentage?
For sit-down service, 15–20% is typical, with 18% a common middle ground. Exceptional service often gets 20% or more.