Key takeaways
- Ten percent of any bill is the bill with the decimal point moved one place left; 15, 18, 20 and 25 percent are simple multiples of that figure.
- US etiquette guides put the tip on the pre-tax amount, but tipping on the total is common and the difference on a typical meal is a dollar or two.
- Add the tip to the bill before dividing by the number of people, and give any leftover cents to one person so the shares sum to the exact total.
- Check your mental math against the 10 percent figure: a tip between one and two times it is between 10 and 20 percent.
Every tip percentage you are likely to use is built from 10 percent, and 10 percent of any bill is the bill with the decimal point moved one place to the left. Once you have that number, 15 percent is it plus half of it, 20 percent is it doubled, and 18 percent is 20 percent minus a tenth of itself. That is the whole method. The rest of this guide is worked examples, the pre-tax question, and splitting the total so the shares add up to the cent.
The 10 percent anchor
Take the bill, move the decimal one place left, and you have 10 percent.
- $50.00 becomes $5.00
- $86.40 becomes $8.64
- $123.75 becomes $12.38 (rounding $12.375)
From there:
| Tip you want | How to get it from 10% | On $50 | On $86.40 |
|---|---|---|---|
| 15% | 10% plus half of 10% | $5.00 + $2.50 = $7.50 | $8.64 + $4.32 = $12.96 |
| 18% | 20% minus a tenth of 20% | $10.00 - $1.00 = $9.00 | $17.28 - $1.73 = $15.55 |
| 20% | 10% doubled | $10.00 | $17.28 |
| 25% | 20% plus 5% (half of 10%) | $10.00 + $2.50 = $12.50 | $17.28 + $4.32 = $21.60 |
If 18 percent feels fiddly, round the bill first. $86.40 is close to $90; 20 percent of $90 is $18, and a little under that is $16 to $17, which is where 18 percent lands ($15.55). Nobody at the table will check the cents.
Tip on the bill before or after tax?
Etiquette guides in the US generally say the tip is on the pre-tax amount, because the tax is not part of the service. In practice many people tip on the total because it is the number at the bottom of the receipt, and the difference is small: on an $80 meal with $6.40 tax, 20 percent is $16.00 before tax and $17.28 after. Either is acceptable. Tipping on the pre-tax amount is the more defensible rule if you want one.
To tip pre-tax in your head, subtract the tax line first, then apply the shortcut. If the receipt does not show tax separately, tip on the total and move on.
Splitting the bill with the tip
Add the tip to the bill first, then divide. Dividing the bill and the tip separately and adding the pieces gives the same answer, but it is more steps and more rounding.
Example: an $80 meal, $6.40 tax, 20 percent tip on the pre-tax amount.
- Tip: 20 percent of $80 = $16.00
- Total: $86.40 + $16.00 = $102.40
- Three people: $102.40 / 3 = $34.13 and a bit
Three shares of $34.13 come to $102.39, one cent short. Give one person $34.14. When a split does not divide evenly, the leftover cents go to one or two people; that is what a tip calculator does automatically, so the shares always sum to the exact total.
For cash, the easier move is to round the total up to a whole dollar and let the tip absorb the difference: $102.40 becomes $103, the tip becomes $16.60 (20.75 percent), and each of three people pays $34.33 and one pays $34.34.
Quick reference by bill size
| Bill | 15% | 18% | 20% |
|---|---|---|---|
| $20 | $3.00 | $3.60 | $4.00 |
| $35 | $5.25 | $6.30 | $7.00 |
| $50 | $7.50 | $9.00 | $10.00 |
| $75 | $11.25 | $13.50 | $15.00 |
| $100 | $15.00 | $18.00 | $20.00 |
| $150 | $22.50 | $27.00 | $30.00 |
The tip calculator prints the same table for whatever bill you enter, at 10, 15, 18, 20 and 25 percent, and has a tax field so the tip is worked out on the pre-tax amount when you want it that way.
What percentage to tip
The shortcut gives you the arithmetic, not the number. In US sit-down restaurants 18 to 20 percent is the common range for standard service and 15 percent is the floor; counter service and takeout are tipped less or not at all; delivery is usually 10 to 20 percent with a minimum of a few dollars. Outside the US, conventions vary widely, and in several countries a service charge is already on the bill. Check the receipt for a line marked service or gratuity before adding a tip on top.
Checking your mental math
The fastest check is 10 percent. If the tip you wrote is between one and two times the 10 percent figure, it is between 10 and 20 percent and you are in the right band. A tip above twice the 10 percent figure is over 20 percent, which may be what you intended, or a decimal slip. If you want the cents exact, the calculator does it in the time it takes to type the bill.
Frequently asked questions
Move the decimal point of the bill one place to the left to get 10 percent, then double it. On a $63.50 bill, 10 percent is $6.35 and 20 percent is $12.70. For 15 percent, add half of the 10 percent figure instead of doubling it.
US etiquette guides say the pre-tax amount, because tax is not part of the service. Many people tip on the total out of habit, and the difference is small: on $80 with $6.40 tax, 20 percent is $16.00 before tax and $17.28 after. Either is acceptable.
Add the tip to the bill first, then divide the total by the number of people and round each share to the cent. If the shares come to a cent or two short, give the extra cents to one or two people. A tip calculator with a split option does this reconciliation automatically.
For table service, 18 to 20 percent is the usual range for standard service and 15 percent is the floor. Counter service and takeout are tipped less or not at all, and delivery is commonly 10 to 20 percent with a small minimum. Check the receipt for a service charge before adding a tip.