Tip on a $45 Bill (15%, 18%, 20%, 25%)
Quick reference for a $45 bill: 15% tip = $6.75 · 18% tip = $8.10 · 20% tip = $9.00 · 25% tip = $11.25
Tip amounts at each common percentage
| Tip % | Tip amount | Total bill |
|---|---|---|
| 10% (minimum) | $4.50 | $49.50 |
| 12% (below average) | $5.40 | $50.40 |
| 15% (standard) | $6.75 | $51.75 |
| 18% (good) | $8.10 | $53.10 |
| 20% (excellent) | $9.00 | $54.00 |
| 22% | $9.90 | $54.90 |
| 25% (outstanding) | $11.25 | $56.25 |
| 30% | $13.50 | $58.50 |
How to calculate any of these in your head
Start with 10% — for a $45 bill, that's $4.50 (just move the decimal one place left).
From there:
- 15% = 10% + 5%: $4.50 + $2.25 = $6.75
- 18% = 20% − 2%: $9.00 − $0.90 = $8.10
- 20% = 10% × 2: $4.50 × 2 = $9.00
- 25% = 20% + 5%: $9.00 + $2.25 = $11.25
- 30% = 10% × 3: $4.50 × 3 = $13.50
If you can do 10% (decimal shift) and halving in your head, you can produce any of the standard tip amounts in about five seconds.
Splitting the bill among friends
Total bill (with 18% tip) is $53.10. Split it among different group sizes:
| Group size | Each pays | Even-up cash |
|---|---|---|
| 2 people | $26.55 | $27 each |
| 3 people | $17.70 | $18 each |
| 4 people | $13.28 | $14 each |
| 5 people | $10.62 | $11 each |
| 6 people | $8.85 | $9 each |
For uneven splits (someone only had a salad, someone had three drinks), people-pay-their-own + proportional share of tip is the fairest approach.
What's the "right" tip percentage in the US?
Tipping norms have shifted upward over the last decade:
- 20% is now the standard for sit-down restaurant service in the US.
- 15% is the new floor — anything lower is widely read as a complaint about the service.
- 18% is "good service" — a sensible default if you're unsure.
- 25%+ signals "outstanding" — bartenders and small-tab servers especially appreciate it.
If you got bad service, communicate with the manager before reducing the tip — servers often have no control over the kitchen, hostess delays, etc. A low tip without explanation is read as "you forgot to add the tip," not "I'm unhappy."
Tipping outside the US
$45 dinners exist worldwide, but the appropriate tip varies wildly by country:
- UK, Australia, NZ: 10% if not included; check for "service charge already added" on the bill.
- Most of Europe: Service is included; round up or leave 5–10% extra for great service.
- Mexico, Argentina: 10% standard.
- Japan: Do not tip. It can be considered rude. Service is already exceptional.
- China, South Korea: Tipping is not customary in local restaurants; varies in high-end hotels.
Tip on the pre-tax or post-tax total?
If your $45 bill is the food total (pre-tax) and adding 8% sales tax brings it to $48.60, you have two options:
- Tip on pre-tax ($45): 20% tip = $9.00. Total: $48.60 + $9.00 = $57.60
- Tip on post-tax ($48.60): 20% tip = $9.72. Total: $48.60 + $9.72 = $58.32
The traditional rule is tip on pre-tax (servers shouldn't be rewarded for taxes), but many people now tip on post-tax for simplicity and generosity. Either is acceptable.
Frequently asked questions
Is 18% a standard auto-gratuity for large parties?
Yes. Most US restaurants automatically add 18–20% gratuity to bills for parties of 6 or more. If the restaurant has done this, you don't need to add an additional tip unless the service was exceptional.
What if I'm paying with a credit card — does that change anything?
Credit card processors charge the server's restaurant a small fee (~3%) on the tip portion too. Some servers slightly prefer cash tips because they receive them in full. But by all means use a card — it's still vastly preferable to not tipping at all.
How do I leave a tip if the bill already includes a service charge?
Read the bill carefully. If "service charge" is listed (typically 15–18%), no additional tip is required. If you want to reward exceptional service further, an additional 5–10% on top is generous.
What's the easiest way to leave 20% if I'm paying in cash?
For a $45 bill, double the 10% (which is $4.50) to get $9. Leave $54 total. If you only have $50s and $5s, leave $55 and consider it tipped at 22%.
Skip the math next time
The tip calculator handles any bill amount, any tip percentage, and any number of people — all in your browser. For shopping, see the discount calculator. For pure percentage math (15% of any number, not just $45), the main percentage calculator is the fastest.