How to Calculate a Tip
Quick mental math methods, standard tipping norms, and worked examples for any situation.
The tip formula
Calculating a tip is straightforward multiplication:
Tip amount = Bill × (Tip % ÷ 100) Total = Bill + Tip amount Per person = Total ÷ Number of people
For a $65 bill with a 20% tip split between 3 people:
Tip = $65 × 0.20 = $13.00 Total = $65 + $13 = $78.00 Each = $78 ÷ 3 = $26.00
Mental math shortcuts
You don't need a calculator if you know these two tricks.
20% tip — move the decimal, then double
Find 10% by moving the decimal one place left, then double it.
$48 bill: 10% = $4.80 20% = $4.80 × 2 = $9.60
15% tip — find 10%, add half
Find 10% by moving the decimal, then add half of that to get 15%.
$48 bill: 10% = $4.80 5% = $4.80 ÷ 2 = $2.40 15% = $4.80 + $2.40 = $7.20
18% tip — use 20%, subtract 10% of the tip
Calculate 20%, then subtract 10% of that result.
$48 bill: 20% = $9.60 10% of $9.60 = $0.96 18% ≈ $9.60 - $0.96 = $8.64
Standard tipping norms in the US
Tip expectations vary by service type. Here's what's considered standard:
| Service | Standard tip | Notes |
|---|---|---|
| Sit-down restaurant | 18–20% | Minimum 15% for acceptable service |
| Food delivery | 15–20% | $3–5 minimum regardless of order size |
| Bartender | $1–2 per drink | Or 15–20% on a tab |
| Taxi / rideshare | 15–20% | More for long trips or help with luggage |
| Haircut / barber | 15–20% | Tip the person who cuts, not the owner |
| Hotel housekeeping | $2–5 per night | Leave daily; staff may change each day |
| Takeout / counter | 10–15% | Optional but appreciated |
| Movers | $20–50 per mover | More for heavy/difficult moves |
Should you tip on the pre-tax or post-tax total?
Technically, tipping on the pre-tax subtotal is correct — you're tipping for the service, not the government's cut. But most people tip on the total for simplicity, and the difference is small.
Example: $60 pre-tax bill, 10% tax, 20% tip.
Pre-tax tip: $60.00 × 20% = $12.00 Post-tax tip: $66.00 × 20% = $13.20 Difference: $1.20
$1.20 on a $60 meal. Not worth stressing over — round up for simplicity.
Frequently asked questions
- What counts as a bad tip?
- Anything below 15% at a sit-down restaurant is generally considered a poor tip in the US. Restaurant servers typically earn a lower base wage with the expectation that tips will make up the difference. Leaving no tip is typically reserved for genuinely bad service — and even then, speaking to a manager is often more effective.
- Do I tip if gratuity is already included?
- No — if the check says "gratuity included" or "service charge included," you do not need to add another tip. Automatic gratuity (usually 18–20%) is common for large groups of 6 or more. Check the bottom of your receipt before adding anything.
- How do I split the bill unevenly?
- Calculate the tip on the full bill first, then divide each person's share of the total proportionally. For example: if 3 people have items totaling $20, $25, and $15 (total $60) and the tip is $12, each person's share of the tip is 20/60, 25/60, and 15/60 of $12 — meaning $4, $5, and $3 respectively.
- Is it rude to use a tip calculator?
- Not at all. Using a calculator ensures accuracy and is far preferable to undertipping by mistake. Most people at the table won't notice, and those who do won't mind.