Tipping: the math, the norms, and why service charges are not tips
Tipping is a straightforward calculation, but tipping norms vary enormously by country, service type, and even city. Understanding both the formula and the context helps you tip appropriately and avoid double-paying when a service charge is already included.
The formula
Tip amount = Bill x (Tip% / 100)
Total = Bill + Tip
Per person = Total / Number of people
For a 2,400 dinner with a 15% tip split among 4:
- Tip = 2,400 x 0.15 = 360
- Total = 2,400 + 360 = 2,760
- Per person = 2,760 / 4 = 690
Tipping norms by country
| Country | Restaurants | Delivery | Taxi |
|---|---|---|---|
| USA | 18-22% | 15-20% | 15-20% |
| UK | 10-15% | Optional | Round up |
| Canada | 15-20% | 10-15% | 15% |
| Australia | 10% (optional) | Optional | Round up |
| Japan | Not customary | Not customary | Not customary |
| India | 10-15% (optional) | Small flat tip | Round up |
In many countries, restaurants add a service charge (typically 5-15%), which appears as a line item on the bill. If a service charge is already included, an additional tip is entirely at your discretion.
The rounding shortcut
For quick mental math: 10% of any bill is just moving the decimal point left one place.
- 10% of 1,350 = 135
- 15% = 10% + 5% = 135 + 67.50 = 202.50
- 20% = 10% x 2 = 270
This works fast enough that you rarely need a calculator, but the tool handles the exact split calculation that mental math struggles with for uneven divides.
When to adjust the tip
Consider going above the standard tip for:
- Exceptional service or unusual effort
- Large group bookings (the server handled complexity)
- Small local restaurants where staff wages are lower
Consider lower or no tip for:
- Pre-counted service charges already on the bill
- Self-service or counter-service contexts
- Genuinely poor service (though speaking to management is usually more productive)