How to Calculate a Tip in Seconds (15%, 18% and 20%)
Calculate a 15%, 18% or 20% tip in your head with the 10% trick, split the bill fairly, decide whether to tip on tax and see typical US tipping norms.
The bill arrives, everyone is looking at you, and you need 18% of $64.50. You don't need a calculator if you know one trick. Here is how to work out any tip quickly, split it between friends and decide what amount is fair.
The 10% trick
To find 10% of any amount, move the decimal point one place to the left. 10% of $64.50 is $6.45. Every common tip builds on that:
- 20%: double the 10%. 6.45 × 2 = $12.90
- 15%: 10% plus half of it. 6.45 + 3.23 = $9.68
- 18%: 20% minus 2% (2% is one fifth of 10%). 12.90 − 1.29 = $11.61
- 25%: divide by 4. 64.50 ÷ 4 = $16.13
Quick tip table
| 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 |
| $64.50 | $9.68 | $11.61 | $12.90 |
| $100 | $15.00 | $18.00 | $20.00 |
| $150 | $22.50 | $27.00 | $30.00 |
The total in one step
To get the total with tip, multiply the bill by 1 plus the tip rate: for 20%, multiply by 1.20. $64.50 × 1.20 = $77.40. For 18%, multiply by 1.18 ($76.11).
Splitting the bill
Add the tip first, then divide. Four friends splitting $64.50 with a 20% tip: 77.40 ÷ 4 = $19.35 each. If people ordered very different amounts, each person can tip on their own share instead.
Tip on the amount before or after tax?
Etiquette guides usually say to tip on the pre-tax amount, because tax isn't part of the service. In practice, many people tip on the total for simplicity; the difference on a $60 meal with 8% tax is under $1 at 20%.
How much to tip in the US
| Service | Typical tip |
|---|---|
| Sit-down restaurant | 15% to 20%, more for great service |
| Bar | $1 to $2 per drink, or 15% to 20% of the tab |
| Food delivery | 15% to 20%, with a few dollars minimum |
| Taxi or rideshare | 15% to 20% |
| Hair salon or barber | 15% to 20% |
| Hotel housekeeping | A few dollars per night |
Norms vary by region and change over time, and in many countries outside the US a service charge is already included in the bill. Check the receipt before adding a tip.
For any other percentage, use the percentage calculator: pick "What is X% of a value?" and enter the tip rate and the bill.
Frequently asked questions
How do I calculate a 20% tip?
Move the decimal point one place left to get 10%, then double it. On $45, 10% is $4.50, so 20% is $9.00.
How do I calculate 15% quickly?
Take 10% and add half of it. On $80: $8 + $4 = $12.
Should I tip on the total with tax?
Etiquette says the pre-tax amount, but tipping on the total is common and the difference is small.
Is 18% a good tip?
Yes. In the US, 18% to 20% is a standard tip for good service at a sit-down restaurant.
Lawyer for almost 20 years, focused on digital law, and creator of CoringaWeb. He writes the guides and builds the tools on this site.
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