Tipping is customary in many countries, particularly the United States, where servers rely on tips as a significant part of their income. Knowing how to quickly calculate the right tip amount — and split it fairly among a group — saves time and avoids the awkward arithmetic at the end of a meal.
The tip formula
To find the total including tip: Total = Bill + Tip Amount. To split evenly: Per Person = Total ÷ Number of People. For example, a 20% tip on an $85 bill: $85 × 0.20 = $17 tip, $102 total.
Standard tip percentages in the US
- 10% — Below average. Reserved for poor service or counter-service restaurants.
- 15% — Minimum acceptable for sit-down restaurants. Was the standard for decades.
- 18% — Common default, especially for parties of 6 or more where auto-gratuity may apply.
- 20% — The modern standard for good table service. The most common tip percentage today.
- 25%+ — Generous. Appropriate for exceptional service, complex orders, or expensive establishments.
Quick mental math tricks for tipping
You don't always need a calculator. Here are fast shortcuts:
- 10% tip: Move the decimal point one place left. $85.00 → $8.50.
- 20% tip: Find 10% and double it. $8.50 × 2 = $17.00.
- 15% tip: Find 10%, then add half of that. $8.50 + $4.25 = $12.75.
- 25% tip: Find 10%, then multiply by 2.5 — or divide the bill by 4. $85 ÷ 4 = $21.25.
Pre-tax vs. post-tax tipping
The traditional approach is to tip on the pre-tax subtotal — the amount before sales tax is added. This makes sense because the tax portion goes to the government, not the server. However, many people tip on the post-tax total for simplicity, and the difference is usually small. On a $100 meal with 8% tax, tipping 20% pre-tax is $20.00 while tipping 20% post-tax is $21.60 — a $1.60 difference.
Tipping beyond restaurants
- Bars: $1–$2 per drink, or 15–20% of the total tab.
- Delivery: 15–20% of the order, with a $3–$5 minimum.
- Hair salons: 15–20% of the service cost.
- Hotels: $2–$5 per night for housekeeping; $1–$2 per bag for bellhops.
- Rideshare: 15–20% for good service, especially for longer rides or help with luggage.