How to Calculate Tip: Simple Methods That Work
Master multiple ways to calculate tips quickly—with or without a calculator
Need a quick answer? Use our instant tip calculator to calculate tips in seconds without any mental math.
Calculating tips doesn't have to be complicated. Whether you're at a restaurant, paying for delivery, or getting a haircut, knowing how to quickly figure out the right tip amount is a valuable skill. This guide teaches you multiple methods so you can choose the one that works best for you.
The Basic Formula
Tip Amount = Bill Amount × Tip Percentage
For example: $50 bill × 20% (0.20) = $10 tip
This formula works for any tip percentage. Just convert the percentage to a decimal (20% = 0.20, 15% = 0.15, 18% = 0.18) and multiply by your bill amount.
Method 1: The Decimal Shortcut (Easiest)
This is the fastest mental math method for calculating tips:
For 20% Tips:
- Step 1: Move the decimal point one place to the left (this gives you 10%)
- Step 2: Multiply that number by 2 (this gives you 20%)
Examples:
Bill: $45.00
• Move decimal left: $4.50 (10%)
• Double it: $4.50 × 2 = $9.00 tip (20%)
Bill: $82.50
• Move decimal left: $8.25 (10%)
• Double it: $8.25 × 2 = $16.50 tip (20%)
Bill: $23.75
• Move decimal left: $2.375 (10%)
• Double it: $2.375 × 2 ≈ $4.75 tip (20%)
For 15% Tips:
- Step 1: Move the decimal left to get 10%
- Step 2: Divide that by 2 to get 5%
- Step 3: Add 10% + 5% = 15%
Example: $40 bill → 10% = $4, 5% = $2, so 15% = $6 tip
Method 2: The Tax Doubling Trick
In states with sales tax around 8-10%, you can use a clever shortcut:
For 20% tip: Simply double the tax amount shown on your receipt
This works because if tax is ~10%, doubling it gives you approximately 20%.
Example:
Subtotal: $48.00
Tax (10%): $4.80
Total: $52.80
Quick tip calculation: $4.80 × 2 = $9.60 tip (20%)
Note: This method is fastest but less precise. It works well for quick estimates, especially when you just want a ballpark figure.
Method 3: The Rounding Method (Quick & Easy)
For those who hate math, just round to make it simple:
Bill: $37.82
Round to $40 → 20% = $8 tip
You're tipping slightly more, but it's easier and servers appreciate it
Bill: $63.45
Round to $65 → 20% = $13 tip
Close enough and no complex math needed
Method 4: Using Your Phone Calculator
If you're okay using your phone, this is the most accurate method:
- Open your phone's calculator app
- Enter your bill amount (e.g., 45.00)
- Multiply by the tip percentage as a decimal:
- • For 15%: multiply by 0.15
- • For 18%: multiply by 0.18
- • For 20%: multiply by 0.20
- • For 25%: multiply by 0.25
- Hit equals to get your tip amount
Even better: Use our dedicated tip calculator which is faster and includes bill splitting features.
Calculating Tips for Common Percentages
10% Tip (Easy Foundation)
Method: Move the decimal point one place to the left
- $30.00 → $3.00
- $85.50 → $8.55
- $124.00 → $12.40
15% Tip
Method: Calculate 10% (move decimal left), then add half of that for 5% more
Example: $50 bill
• 10% = $5.00
• 5% (half of 10%) = $2.50
• 15% tip = $5.00 + $2.50 = $7.50
18% Tip
Method 1: Calculate 20% then subtract 2%
Method 2: Calculate 10% + 8% (10% minus 2%)
Example: $60 bill
• 10% = $6.00
• 8% = $4.80
• 18% tip = $6.00 + $4.80 = $10.80
20% Tip (Most Common)
Method: Move decimal left (10%), then double it
- $25.00 → 10% = $2.50 → 20% = $5.00
- $74.50 → 10% = $7.45 → 20% = $14.90
- $110.00 → 10% = $11.00 → 20% = $22.00
25% Tip
Method: Calculate 10%, then add 10% again, then add 5% (half of 10%)
Example: $40 bill
• 10% = $4.00
• 10% again = $4.00
• 5% = $2.00
• 25% tip = $4 + $4 + $2 = $10.00
Splitting Bills: How to Calculate Tips for Groups
When dining with friends, calculate the tip first, then divide:
Step-by-Step Group Tipping:
- Calculate tip on total bill (e.g., $100 × 20% = $20 tip)
- Add tip to bill ($100 + $20 = $120 total)
- Divide by number of people ($120 ÷ 4 people = $30 per person)
Pro tip: Use our tip calculator with bill splitting to avoid any math errors when dividing among groups.
Quick Reference: Tip Calculation Cheat Sheet
| Bill Amount | 15% Tip | 18% Tip | 20% Tip | 25% Tip |
|---|---|---|---|---|
| $20 | $3.00 | $3.60 | $4.00 | $5.00 |
| $30 | $4.50 | $5.40 | $6.00 | $7.50 |
| $50 | $7.50 | $9.00 | $10.00 | $12.50 |
| $75 | $11.25 | $13.50 | $15.00 | $18.75 |
| $100 | $15.00 | $18.00 | $20.00 | $25.00 |
| $150 | $22.50 | $27.00 | $30.00 | $37.50 |
Common Mistakes to Avoid
❌ Mistake #1: Tipping on the total with tax, then adding more
Choose one method—tip on pre-tax OR post-tax, not both. You might be accidentally over-tipping.
❌ Mistake #2: Forgetting to move the decimal when calculating 10%
$45 × 10% = $4.50, not $45. Don't forget to divide by 10 or move the decimal left.
❌ Mistake #3: Not tipping on discounted amounts
If you used a coupon or got 50% off, tip based on the original price. Your server did the same work.
❌ Mistake #4: Miscalculating when splitting bills
Always calculate tip on the full bill first, then split. Don't have each person calculate their own tip portion—it leads to undertipping.
When to Use Which Method
- At a busy restaurant: Use the decimal shortcut (fastest mental math)
- When accuracy matters: Use your phone calculator or our tip calculator
- For quick estimates: Use the tax doubling trick or rounding method
- With groups: Always use a calculator to avoid splitting errors
- When stressed or tired: Just use a tip calculator—no shame in that!
🧮 The Easiest Solution
Honestly? Most people find mental math stressful at the table. That's why we built our tip calculator—it's faster, more accurate, and includes bill splitting.
No math needed. Just enter your bill, select a percentage, and done. Perfect for when you just want to eat in peace.
Practice Problems
Test your tip calculation skills with these practice scenarios:
Problem 1
Your dinner bill is $67.80. You want to leave a 20% tip. How much should you tip?
Show Answer
10% = $6.78
20% = $6.78 × 2 = $13.56 tip
Total: $67.80 + $13.56 = $81.36
Problem 2
You and 3 friends have a $120 bill. You want to leave 18% tip and split evenly. How much does each person pay?
Show Answer
18% tip = $120 × 0.18 = $21.60
Total with tip = $120 + $21.60 = $141.60
Per person = $141.60 ÷ 4 = $35.40 each
Problem 3
Your bill is $43.25. You had exceptional service and want to leave 25%. What's your tip?
Show Answer
10% = $4.33
20% = $8.66
5% = $2.16
25% = $8.66 + $2.16 = $10.82 tip
Or round up to $11.00 for simplicity!