How to Calculate a Tip (and Split the Bill)
Guide · Updated
To calculate a tip, multiply the bill by the tip rate as a decimal: a 20% tip on a $50 bill is 50 × 0.20 = $10, for a $60 total. To split it, divide that total by the number of people. In the U.S., 15–20% on the pre-tax amount is the standard range for sit-down restaurant service.
The basic formula
A tip is just a percentage of your bill. To turn a percentage into a number you can multiply, divide it by 100: 15% becomes 0.15, 18% becomes 0.18, and 20% becomes 0.20. Then multiply the bill by that decimal. So a 20% tip on a $40 bill is 40 × 0.20 = $8, and your grand total is 40 + 8 = $48.
If you'd rather do it in your head, the 20% shortcut is the easiest one to remember: take 10% of the bill by moving the decimal point one place to the left ($40 becomes $4.00), then double it ($8). For 15%, take that same 10% figure and add half of it again ($4.00 + $2.00 = $6.00). These mental tricks get you close enough to round to a comfortable number.
When the math gets awkward — odd cents, an unusual percentage, or a large party — it's faster and less error-prone to let a tool do it. A tip calculator handles the multiplication, the total, and the per-person split in one step.
What percentage should you tip?
Tipping norms vary by country and by the type of service, so there is no single 'correct' number. In the United States, where many service workers earn a lower base wage and rely on tips, the customary range for table service is roughly 15% to 20% of the pre-tax bill, with 18–20% common for good service. The figures below reflect widely cited U.S. norms; in many European and Asian countries a service charge is already included and tipping is modest or optional.
Use these as a starting point, then adjust up for exceptional service or a large, demanding party, and down (within reason) for genuinely poor service. For counter service where you order and pick up your own food, a tip is optional and a smaller amount or none is normal.
| Situation | Typical U.S. tip |
|---|---|
| Sit-down restaurant, standard service | 15–20% of pre-tax bill |
| Exceptional table service / large party | 20% or more |
| Food delivery | 10–15% (often $3–5 minimum) |
| Bartender | $1–2 per drink, or 15–20% of tab |
| Taxi / rideshare | 10–15% |
| Hairdresser / barber | 15–20% |
| Coffee shop / counter service | Optional; round up or 0–10% |
Quick tip reference table
If you want to skip the math entirely, the table below shows the tip amount for common bill totals at the three most-used rates, plus what the bill comes to once a 20% tip is added. Every value is the bill multiplied by the rate (for example, $75 × 0.18 = $13.50).
Notice the pattern: the 18% column always sits exactly halfway between the 15% and 20% columns, and the 20% tip is always one-third larger than the 15% tip. Once you internalize a couple of these, you can interpolate any bill in between.
| Bill | 15% tip | 18% tip | 20% tip | Total with 20% tip |
|---|---|---|---|---|
| $20 | $3.00 | $3.60 | $4.00 | $24.00 |
| $30 | $4.50 | $5.40 | $6.00 | $36.00 |
| $40 | $6.00 | $7.20 | $8.00 | $48.00 |
| $50 | $7.50 | $9.00 | $10.00 | $60.00 |
| $75 | $11.25 | $13.50 | $15.00 | $90.00 |
| $100 | $15.00 | $18.00 | $20.00 | $120.00 |
| $150 | $22.50 | $27.00 | $30.00 | $180.00 |
Splitting the bill among people
The cleanest way to split a tipped bill evenly is to calculate the tip on the whole bill first, add it to the total, and only then divide by the number of people. For a $100 bill with a 20% tip, that's $100 + $20 = $120, divided by 4 people = $30 each. Splitting first and tipping each share separately gives the same answer mathematically, but doing the tip once avoids rounding drift.
Even splits rarely land on round numbers. $120 across 7 people is about $17.14 each — so it's common for one person to cover the odd cents or for everyone to round up slightly, which quietly bumps the tip a little higher. That's fine; the staff benefit and nobody has to fish for pennies.
When people ordered very differently — one person had a steak and a cocktail, another had a side salad — an even split feels unfair. In that case, split by what each person actually ordered (an 'itemized' split), then apply the same tip percentage to each person's subtotal so everyone tips proportionally to what they spent. A calculator that supports per-person splitting removes the arithmetic headache for both methods.
Tip on the pre-tax amount or the total?
Sales tax is a government charge that has nothing to do with your server, so the technically 'correct' base for a tip is the pre-tax subtotal. Tipping on the pre-tax amount is the convention most etiquette guides recommend. On a $50 meal with $4 of sales tax, tipping 20% on the $50 subtotal is $10, whereas tipping on the $54 post-tax total is $10.80 — a small difference that grows with the size of the bill.
In practice, many people simply tip on the total because it's the number printed at the bottom of the receipt and the gap is minor. Either is socially acceptable; just pick one and be consistent. If your sales tax happens to be close to 8–10%, a handy shortcut some diners use is to double the tax line as a rough 20% tip — but that only works in those specific tax brackets, so verify the rate for your area.
Watch for a service charge or 'gratuity included' line, which restaurants often add automatically for large parties. If gratuity is already on the bill, an additional tip is optional. To separate the tax from the food, knowing your local rate helps — a sales tax calculator can break out the tax, and a percentage calculator handles any custom rate you want to apply.
Common mistakes to avoid
The most frequent error is tipping on the wrong base — accidentally applying the percentage to the post-tax-and-tip grand total instead of the food subtotal, which inflates what you owe. Another is double-tipping: adding a tip on top of an automatic service charge that already covers gratuity. Always read the itemized receipt before you sign.
When splitting, avoid having each person eyeball their own tip on a rounded-down share, because the rounding compounds and the total tip can fall short of what you intended. Calculate the full tip once, then split. And remember that tip percentages apply to the bill amount, not to each person's headcount — a 20% tip is 20% whether two people or ten are at the table.
If you tip frequently or split with the same group often, bookmark a calculator so the numbers are never in doubt. It takes the guesswork out of the moment the check arrives and keeps the split fair for everyone.
Frequently asked questions
How do I calculate a 20% tip quickly?
Move the decimal point one place left to get 10% of the bill, then double it. For a $45 bill, 10% is $4.50, so 20% is $9.00. Add it to the bill for a $54.00 total.
Should I tip on the pre-tax or post-tax amount?
Etiquette guides generally recommend tipping on the pre-tax subtotal, since sales tax isn't part of the service. Many people tip on the total for simplicity; the difference is small, so either is acceptable as long as you're consistent.
What's the standard tip at a U.S. restaurant?
For sit-down table service, 15–20% of the pre-tax bill is customary, with 18–20% common for good service. Counter and takeout service is optional and usually lower or nothing.
How do I split a bill with a tip among friends?
Calculate the tip on the full bill, add it to get the grand total, then divide by the number of people. For a $100 bill with a 20% tip, that's $120 split four ways, or $30 each.
Do I still tip if there's a service charge?
If the bill already includes a service charge or 'gratuity included' line — common for large parties — an additional tip is optional. Check the itemized receipt so you don't tip twice.
Is it rude not to tip?
In the U.S., where many service workers depend on tips, leaving little or nothing for normal table service is considered poor etiquette. Norms differ abroad, where a service charge is often included and tipping is modest or optional.
Try the tools
Sources & references
This guide is general information to help you understand the topic and use the tools — it is not professional (financial, medical, legal, or tax) advice. Verify anything important before relying on it. See our Disclaimer.