How Much Should You Tip at a Restaurant — and How Do You Split It Fairly?
The math behind a tip is simple, but the questions around it rarely are: is it before or after tax, what if the group ordered different amounts, and what's actually a "good" percentage? Here's a practical walkthrough, with a calculator that handles all three cases.
Short answer: Tip = Subtotal × Percentage ÷ 100, using the bill amount before sales tax. A $60 subtotal with a 20% tip is $60 × 20 ÷ 100 = $12, for a $72 grand total.
A tip is a voluntary amount added on top of the bill to thank a server for their work. In the US it's less "optional" than it sounds — many servers are paid a reduced base wage under the assumption that tips make up the rest, which is part of why 15–25% has become the customary range rather than a rare bonus.
You don't need to do the math in your head. The tip calculator lets you pick a 15/18/20/25% preset based on how the service was, or type in any custom percentage, and it calculates the exact dollar amount instantly.
Example: tip amount at common bill totals (illustrative figures)
Bill subtotal
15%
18%
20%
25%
$20
$3.00
$3.60
$4.00
$5.00
$60
$9.00
$10.80
$12.00
$15.00
$100
$15.00
$18.00
$20.00
$25.00
Rule of thumb: for 20%, take 10% of the bill (move the decimal one place) and double it. For 15%, take that same 10% and add half again.
Splitting the bill among a group
Short answer: Per person = (Subtotal + Tip) ÷ Number of people. Add the tip to the subtotal first, then divide the grand total by the group size.
Say, hypothetically, a table of three people has a $60 subtotal and decides on a 20% tip ($12), bringing the grand total to $72. Split three ways, that's $24.00 each — a clean, even split that works well when everyone ordered roughly the same amount.
The tool's "Tip & Split" mode does this automatically: enter the subtotal, pick a tip rate, set the number of people, and the per-person amount appears instantly. There's also an optional rounding setting, so a group can round the total or the per-person share up or down to a friendlier number without changing what actually gets collected.
When everyone ordered something different
Short answer: Use an uneven, proportional split — enter what each person's food and drinks actually came to, and the tip gets divided in proportion to those amounts, not split evenly.
An even split feels unfair fast when one person had an appetizer and a soda while another ordered a steak and two cocktails. In this scenario (a purely illustrative example), if one diner's order came to $15 and another's came to $45 on a $60 total bill, the person who ordered three times as much should reasonably cover three times as much of the tip too, not an equal share.
The calculator's "Uneven Split" mode is built for exactly this: add each person's name and their own order total, and it works out each person's proportional share of the tip along with their full amount owed, shown separately per person.
Before tax or after tax?
Short answer: The US convention is to tip on the subtotal before sales tax, not the tax-included total.
Sales tax has nothing to do with how good the service was, so calculating the tip only on the pre-tax subtotal is both the standard etiquette and, in practice, a slightly smaller tip amount than tipping on the full receipt total. If your receipt only shows a combined, tax-included number, the calculator has an "Advanced settings" option to back the sales tax out first — enter your local tax rate and it'll compute the pre-tax subtotal before applying the tip percentage.
Some restaurants also add an automatic service charge or "auto-gratuity" for large parties, commonly six or more guests. If that's already on the receipt, there's a field to account for it so you're not unintentionally tipping on top of a mandatory charge.
In the US, the customary range at full-service restaurants is 15% to 25% of the pre-tax subtotal. 15% is typically seen as fair for adequate service, 18% for good service, 20% is the most common tip for good-to-great service, and 25% is reserved for exceptional service. These are cultural norms, not fixed rules — the final amount is always your call.
Do you tip before or after tax?
The US convention is to calculate the tip on the subtotal before sales tax, not on the tax-included total. Sales tax doesn't reflect service quality, so tipping on the pre-tax amount is both standard etiquette and slightly cheaper for you. If your receipt only shows a tax-included total, back the tax out first before applying the tip percentage.
How do you split a bill evenly among a group?
Add the tip to the subtotal to get the grand total, then divide by the number of people: Per person = (Subtotal + Tip) ÷ People. For example, a $60 bill with a 20% tip ($12) comes to $72 total; split between 3 people that's $24 each.
What if everyone ordered a different amount?
Use an uneven, or proportional, split: enter what each person's food and drinks came to, and divide the tip in proportion to those amounts, not evenly. Someone who ordered a $30 entrée pays a bigger share of the tip than someone who had a $10 salad, and each person's total is shown separately so nobody over- or underpays.
Is tipping mandatory in the US?
No, tipping is not a legal requirement in most cases, though it is a strong cultural expectation since many servers are paid a reduced base wage on the assumption that tips make up the difference. The exception is an automatic service charge or auto-gratuity, which some restaurants add for large parties (commonly 6 or more people) — this is a mandatory line item on the receipt, and any tip on top of it is optional.
Methodology note: Percentages and bill figures in the examples above are illustrative, not statistical claims about actual tipping behavior. Tipping norms vary by region, venue, and personal judgment — this guide describes common US restaurant convention, not a legal or universal rule. It is for general informational purposes only.