Percentage Calculator
Appliance Location: The Measuring Cups Math ToolHow to Calculate Percentages
Our percentage calculator handles four common calculations:
- What is X% of Y? Enter percentage and number to find the exact value (e.g., 20% of 200 = 40).
- X is what % of Y? Enter two numbers to find the percentage relationship (e.g., 40 out of 200 = 20%).
- Percentage Change: Enter original and new values to calculate increase/decrease percentage.
- Add/Subtract Percentage: Add or subtract a percentage from any number (e.g., add 10% to 200 = 220).
🔥 Quick Percentage Reference for Shopping
| Discount | You Pay (on $100) | You Save | Real-world example |
|---|---|---|---|
| 10% off | $90.00 | $10.00 | Seasonal clearance |
| 15% off | $85.00 | $15.00 | Members-only sale |
| 20% off | $80.00 | $20.00 | Black Friday deal |
| 25% off | $75.00 | $25.00 | Outlet promotion |
| 30% off | $70.00 | $30.00 | Inventory clearance |
| 50% off | $50.00 | $50.00 | Half-price event |
🍽️ Tip & Tax Quick Table (US standards)
| Service / Tax | Percentage | On $50 bill | On $100 bill |
|---|---|---|---|
| Poor service tip | 10% | $5.00 | $10.00 |
| Standard tip | 15% | $7.50 | $15.00 |
| Good service tip | 18% | $9.00 | $18.00 |
| Excellent tip | 20% | $10.00 | $20.00 |
| Average sales tax (US) | ~8% | $4.00 | $8.00 |
| High sales tax (e.g., CA) | ~10% | $5.00 | $10.00 |
📚 Grade & Score Percentage Table
| Score (correct/total) | Percentage | Letter Grade (US) | Performance |
|---|---|---|---|
| 45/50 | 90% | A- | Excellent |
| 42/50 | 84% | B | Very Good |
| 35/50 | 70% | C- | Satisfactory |
| 28/50 | 56% | F | Needs Improvement |
| 18/20 | 90% | A- | Excellent |
| 14/20 | 70% | C- | Satisfactory |
🧮 Fraction to Percentage Conversion Table
| Fraction | Decimal | Percentage | Common Use |
|---|---|---|---|
| 1/10 | 0.10 | 10% | Tip on poor service |
| 1/5 | 0.20 | 20% | Standard tip, discount |
| 1/4 | 0.25 | 25% | Quarter, large discount |
| 1/3 | 0.3333 | 33.33% | One-third share |
| 1/2 | 0.50 | 50% | Half, sale discount |
| 3/4 | 0.75 | 75% | Three-quarters |
| 2/3 | 0.6667 | 66.67% | Majority vote |
| 1/8 | 0.125 | 12.5% | Small portion |
Frequently Asked Questions
What is a percentage?
A percentage is a number or ratio expressed as a fraction of 100. It is denoted using the percent sign (%). For example, 45% means 45 out of 100.
How do I calculate percentage of a number?
Multiply the number by the percentage (as a decimal). Example: 25% of 80 = 80 × 0.25 = 20. Or use our calculator's "What is X% of Y?" section.
How do I calculate percentage increase?
(New Value - Original Value) ÷ Original Value × 100 = % Increase. Example: (120 - 100) ÷ 100 × 100 = 20% increase.
How do I calculate percentage decrease?
(Original Value - New Value) ÷ Original Value × 100 = % Decrease. Example: (80 - 60) ÷ 80 × 100 = 25% decrease.
What is the difference between percentage point and percent?
Percentage point is the arithmetic difference between two percentages. Example: going from 40% to 50% is a 10 percentage point increase, but a 25% relative increase.
Is this tool free to use?
Yes, completely free with no usage limits. Calculate as many percentages as you need for shopping, tipping, taxes, or data analysis.
