To calculate a tip at a restaurant, multiply the bill by your chosen percentage divided by 100 (tip = bill × percentage ÷ 100), then add that amount to the bill to get the total. A $50 bill at 20% produces a $10 tip and a $60 total, while the same bill at 18% produces a $9 tip and a $59 total — a one- or two-point swing that adds up over a year of dinners out. In the United States, the widely cited baseline for sit-down restaurant service is 15% for adequate service, 18–20% for good service, and 25% or more for exceptional service, and those figures usually apply to the pre-tax subtotal. Splitting the bill is where the math gets clumsy by hand: a $96 total divided three ways is $32.00 exactly, but a $100 total split three ways is $33.33, $33.33, and $33.34 — or $33.33 each with a leftover cent someone has to absorb. A free browser-based Tip Calculator handles all of that in one screen, so the only decision you make is which percentage to pick.
The Tip Formula, in One Line
The math behind every tip is the same three-step sequence, no matter the restaurant or the size of the party. First, convert the percentage into a decimal by dividing it by 100 — 20% becomes 0.20, 18% becomes 0.18, 15% becomes 0.15. Second, multiply the bill by that decimal to get the tip amount. Third, add the tip to the bill to get the total you actually pay.
Written as one expression, the formula is:
- Tip = bill × (percentage ÷ 100)
- Total = bill + tip
- Per person = total ÷ number of people
- Tip per person = tip ÷ number of people
That is the entire method. The reason it trips people up at the table is not the formula itself, but the small details around it — which number on the receipt to apply it to, how to handle sales tax, what counts as fair service, and how to divide a number that does not split evenly. The sections below walk through each of those decisions.
Standard Restaurant Tipping Norms in the US
Tipping expectations vary by the type of service you receive, not just by the bill total. A sit-down dinner with a server who takes your order, refills drinks, and brings the check is a different experience from picking up a takeout bag at the counter or handing a pizza to a delivery driver. The table below summarizes the most commonly cited US baselines for restaurant-adjacent service.
| Service Type | Typical Tip Range | Notes |
|---|---|---|
| Sit-down restaurant (adequate) | 15% | Floor for full table service in the US |
| Sit-down restaurant (good service) | 18–20% | The most common range at full-service restaurants |
| Sit-down restaurant (exceptional) | 25%+ | For standout effort on special requests, timing, or substitutions |
| Counter service / takeout | 0–10% | No table service; tip jars common but not required |
| Bar (drinks) | $1–2 per drink, or 15–20% of tab | Per-drink is typical when ordering rounds |
| Delivery driver | 10–15%, or $3–5 minimum | Minimum protects drivers on small orders |
These figures are a US-centric baseline rather than a universal rule. International norms differ substantially — many restaurants in Europe, Australia, and parts of Asia include service in the bill, and a tip is genuinely optional. If you are traveling or hosting visitors, the right amount is whatever the local custom considers polite.
Pre-Tax or Post-Tax: Which Amount Do You Tip On?
Restaurant checks in the US almost always list two amounts: a pre-tax subtotal and a post-tax total that includes sales tax. Etiquette writers generally agree that tipping on the pre-tax subtotal is perfectly acceptable, because sales tax is not part of the service your server provided — it is a pass-through to the state. Many people tip on the post-tax total anyway for convenience, and that yields a slightly larger tip in the server's pocket.
The difference is small in percentage terms but real in dollars. On a $100 pre-tax bill in a jurisdiction with 8% sales tax, the post-tax total is $108. A 20% tip on the pre-tax subtotal is $20.00; a 20% tip on the post-tax total is $21.60. Neither is wrong. The decision is yours, and the calculator applies your chosen percentage to whatever number you enter, so you stay in control.
For a deeper walk-through of this decision, the guide Calculate Tip Before or After Tax the Right Way covers the same question from a different angle.
How to Calculate Tip and Split a Restaurant Bill
For a sit-down meal with a server, the cleanest workflow is to figure out the tip first, then split the resulting total by the number of diners. The Tip Calculator runs through the entire sequence in your browser as you type.
- Enter your bill amount in dollars. Use the pre-tax subtotal for a strict tip, or the post-tax total for a rounder figure.
- Choose a tip percentage. The calculator offers quick-tap buttons for 10%, 15%, 18%, 20%, and 25%, or you can type a custom value if your group has agreed on something different.
- Set the number of people splitting the check. The display updates instantly.
- Read the tip, the grand total, and the per-person amount. The per-person figure includes each diner's share of the tip, so nobody has to do mental math after the meal.
Everything runs locally on your device — there is no account to create, nothing to install, and no data sent to a server. That matters in a restaurant setting where the bill total and the names on your credit card are sensitive.
A Worked Example: Dinner for Four
Suppose four friends share a meal with an $80 pre-tax subtotal, $86.40 after 8% sales tax, and the group agrees on an 18% tip on the pre-tax amount.
Step 1 — Tip: 18% of $80 = 80 × (18 ÷ 100) = 80 × 0.18 = $14.40.
Step 2 — Total: $80 (subtotal) + $14.40 (tip) = $94.40. Note that this total does not include the $6.40 in sales tax, which the restaurant collects separately.
Step 3 — Per person: $94.40 ÷ 4 = $23.60 each.
For comparison, tipping on the post-tax total at the same 18% rate gives 86.40 × 0.18 = $15.55 (rounded to the nearest cent), a total of $86.40 + $15.55 = $101.95, and $101.95 ÷ 4 = $25.49 per person. Both approaches are reasonable; the figures just differ by about $1.89 per diner.
When the Bill Doesn't Split Cleanly
Most restaurant totals do not divide evenly by the number of diners. A $94.40 bill split four ways works out to $23.60 per person, but a $95 bill split three ways is $31.666…, and a $100 bill split three ways is $33.333…. The Tip Calculator rounds each share to the nearest cent so the on-screen figures are usable, but the underlying division always produces a leftover fraction somewhere.
In practice, three small habits handle this gracefully:
- Have one person absorb the leftover cent or two. On a single meal, the difference is trivial and the group moves on faster.
- Round each share up to the next clean number — for example, $33.34 to $34.00 each — and treat the extra as an additional tip. This is the simplest approach when the group is feeling generous.
- Tip on the post-tax total, which usually nudges the per-person figure into a slightly rounder number and removes one source of friction.
Adjusting the Tip for Service Quality
The percentages above assume baseline expectations, but the tip is also the most direct feedback you can give a server. Going up or down by a few points signals how the experience landed. A few situations that often move the needle:
- Large parties may include a built-in gratuity of 18–20% already added to the bill. Check the receipt before adding a second tip on top.
- If the server handled a complicated allergy, substitution, or timing request gracefully, moving from 18% to 20% or 25% reflects that without much extra cost.
- If service was genuinely poor — long waits with no acknowledgment, wrong orders, lack of refills — going to 10% sends a clear signal without skipping the tip entirely.
The right number always depends on the meal, the service, and your budget, but the calculation itself does not change: bill times percentage, plus the bill, divided by the number of diners. Running those three steps through the calculator turns the awkward end-of-meal moment into a single screen that the whole table can see.