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.