How to Calculate Restaurant Tips: 15% vs 18% vs 20% Guide

The Tipping Percentages

In the United States, standard restaurant tipping is:

Most people tip 18-20% for standard good service.

Key Rule: Tip on the Total AFTER Tax

This is critical: Tip on the bill AFTER tax is added, not before.

Why? Servers provide the same service regardless of your state's tax rate.

Example: $100 bill, 8% tax, 18% tip

❌ Wrong: $100 × 0.18 = $18 tip ✅ Correct: ($100 + $8 tax) = $108 × 0.18 = $19.44 tip

The server gets $1.44 more because the tip includes tax.

How to Calculate Each Percentage

15% Tip Formula

Tip = (Subtotal + Tax) × 0.15

Example: $85 bill with $6.80 tax

• Total: $85 + $6.80 = $91.80
• Tip: $91.80 × 0.15 = $13.77
• You pay: $91.80 + $13.77 = $105.57

18% Tip Formula

Tip = (Subtotal + Tax) × 0.18

Example: Same $85 bill

• Total after tax: $91.80
• Tip: $91.80 × 0.18 = $16.52
• You pay: $91.80 + $16.52 = $108.32

20% Tip Formula

Tip = (Subtotal + Tax) × 0.20

Example: Same $85 bill

• Total after tax: $91.80
• Tip: $91.80 × 0.20 = $18.36
• You pay: $91.80 + $18.36 = $110.16

Real Restaurant Examples

Scenario 1: Casual Lunch

• Subtotal: $45
• Tax (7%): $3.15
• Total: $48.15

Scenario 2: Nice Dinner

• Subtotal: $120
• Tax (8%): $9.60
• Total: $129.60

Scenario 3: Quick Breakfast

• Subtotal: $25
• Tax (6%): $1.50
• Total: $26.50

Mental Math Tricks (No Calculator Needed)

The 10% + Half Method (Works for 15%)

1. Find 10% (move decimal left): $129.60 → $12.96
2. Find 5% (half of 10%): $12.96 ÷ 2 = $6.48
3. Add them: $12.96 + $6.48 = $19.44 tip (15%)

The 20% Method (Divide by 5)

Tip = Total ÷ 5

• $129.60 ÷ 5 = $25.92 tip (20%)

The Double Tax Method (Approximate 18-20%)

1. Calculate tax: $129.60 × 0.08 = $10.40 (roughly)
2. Double it: $10.40 × 2 = ~$20.80 tip

This gives approximately 16-20% depending on your tax rate.

Common Tipping Questions

Q: Should I Tip on Takeout?

A: Tipping on takeout is optional but appreciated. 10% is typical if you do.

Q: What About Group Dinners?

A: Tip on the total bill for the group. Divide evenly only if splitting payment.

Q: Should I Tip on Alcohol?

A: Yes, tip on your full bill including alcoholic drinks. Standard percentage applies to everything.

Q: What if Service Was Bad?

A: 10-12% is acceptable for poor service. Consider speaking with management about serious issues.

Q: Do I Round Up or Down?

A: Round up. Never round down. Servers depend on tips as income.

Tools for Quick Calculations

• Tip Calculator with Tax - Calculate exact tip instantly
• Percentage of a Number - Find any tip percentage
• What Percent is A of B - Verify your math

The Bottom Line

Restaurant tipping is 15% for adequate, 18% for good, 20%+ for excellent. Always calculate on the post-tax total. Use our tip calculator to get exact amounts in seconds.

Tip well—servers earn minimum wage plus tips.

Try It Yourself

If you want to explore more tools like this, check out our full collection of online percentage calculators for everything from discounts to tax and profit margin formulas.