How to Calculate a Tip

The tip formula

Every tip calculation comes down to one formula:

To get your total, add the tip to the bill: Total = Bill + Tip.

For a $48 bill with a 20% tip: $48 × (20 ÷ 100) = $48 × 0.20 = $9.60 tip. Total = $48 + $9.60 = $57.60.

That's the complete calculation. Everything below is about doing it faster, or in edge cases where there's a decision to make.

Step-by-step worked example

Say your restaurant bill comes to $63 and you want to leave a 20% tip.

1. Find 10% by moving the decimal one place left: $63 → $6.30
2. Double it to get 20%: $6.30 × 2 = $12.60
3. Add to the bill: $63 + $12.60 = $75.60 total

That's the fastest mental math method for 20% — and it works for any bill amount. No multiplication required.

Quick tip reference table

Common bill amounts and tip amounts at the three most common percentages:

Bill	15% tip	18% tip	20% tip	25% tip
$20	$3.00	$3.60	$4.00	$5.00
$30	$4.50	$5.40	$6.00	$7.50
$40	$6.00	$7.20	$8.00	$10.00
$50	$7.50	$9.00	$10.00	$12.50
$60	$9.00	$10.80	$12.00	$15.00
$75	$11.25	$13.50	$15.00	$18.75
$100	$15.00	$18.00	$20.00	$25.00
$125	$18.75	$22.50	$25.00	$31.25
$150	$22.50	$27.00	$30.00	$37.50
$200	$30.00	$36.00	$40.00	$50.00

Mental math shortcuts for every percentage

You don't always need the formula. Here are fast shortcuts for the four most common tip percentages:

15% tip: Find 10% (move decimal left), then find 5% (half of 10%), then add them. On $44: 10% = $4.40, 5% = $2.20, total = $6.60.

18% tip: Find 20% (double the 10%), then subtract 10% of that. On $60: 20% = $12, subtract 10% of $12 = $1.20, so 18% = $10.80.

20% tip: Move the decimal left (10%), then double it. On $53: 10% = $5.30, doubled = $10.60.

25% tip: Find 10%, then multiply by 2.5. On $40: 10% = $4, × 2.5 = $10. Or find 20% and add half of that: $8 + $4 = $12. Both work.

Pre-tax vs. post-tax: which base do you tip on?

Etiquette guides — including Emily Post — recommend tipping on the pre-tax subtotal. The reasoning: sales tax goes to the government, not the restaurant or the server, so there's no reason the server's tip should include a share of it.

In practice, the difference is small enough that most people just tip on whatever number appears most prominently on the receipt. On a $60 bill with 9% tax, the tax is $5.40, making the post-tax total $65.40. A 20% tip on $60 is $12.00; on $65.40 it's $13.08. The server gets $1.08 more if you use the post-tax figure.

Either approach is socially acceptable. If you're unsure, the tip calculator lets you enter either the subtotal or the post-tax total and calculates from whichever you provide.

How tip percentages have shifted over time

The commonly cited 15% restaurant tip standard is now largely outdated for sit-down dining. The practical baseline has shifted to 18–20% over the past decade, driven by higher urban costs of living, greater public awareness of server wages, and the influence of digital payment systems that default to 20% or higher as the lowest suggested option.

That said, 15% remains entirely appropriate for counter service, takeout, or situations where table service was minimal. Context matters: a 15% tip at a full-service dinner is read differently than a 15% tip for a coffee handed over the counter. The US tipping guide breaks down appropriate ranges for 25+ different service types.

Calculating tips on large or discounted bills

Two scenarios trip people up regularly. The first is a large group bill where the restaurant has already added a service charge. Check your receipt carefully — if 18–20% gratuity is listed as a line item, adding a second tip on top is optional and usually at your discretion based on service quality. Most restaurants add automatic gratuity for parties of six or more.

The second is a discounted or promotional bill. If you have a Groupon, a restaurant week deal, or any other promotional discount, the general rule is to tip on the original pre-discount price, not the promotional total. The server provided full service regardless of the deal you got. On a $90 meal bought at $45 on a promotion, tip on $90. The same principle applies to food delivery tips — tip on the original food price, not the discounted checkout total.

When a tip is optional vs. expected

A useful heuristic: if someone came to your table (or your location) and provided ongoing service — refilling drinks, taking multiple orders, checking in — tipping 18–20% is expected. If you walked up to a counter, placed an order, and picked it up yourself, tipping is optional.

The rise of tablet payment systems has placed tip prompts in contexts where they were historically uncommon — bakeries, coffee shops, fast-casual restaurants, self-checkout. You are not obligated to tip in these situations. A 0% selection is socially acceptable at a counter-service coffee shop even if the screen defaults to 20% as the minimum option. For a detailed breakdown by situation, see the full tipping guide.

Splitting a bill with tip

The cleanest method: calculate the full total including tip first, then divide by the number of people. On a $96 bill at 20%: tip = $19.20, total = $115.20. Split four ways: $115.20 ÷ 4 = $28.80 each.

If different people ordered very different amounts, split the pre-tip bill proportionally first, then calculate each person's tip on their share. The tip calculator has a built-in bill splitter that does this automatically.

A common mistake is to divide the pre-tip bill, then each person adds their own tip separately — this can result in uneven tip totals and confusion for the server. Settling the full tipped amount and splitting that is cleaner.

Frequently asked questions

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