Percentage Calculator
6 ways to calculate percentages — fast, free, and accurate
💡 Tip: Press Enter to calculate | Ctrl+D for dark mode
What is X% of Y?
e.g. What is 20% of 150?
X is what % of Y?
e.g. 30 is what % of 150?
Percentage Change
Increase or decrease from one value to another
Add % to a Number
e.g. Add 15% tip to $85 bill
Subtract % from a Number
e.g. 20% off $200 shoes
Percentage Difference
Difference between two values as a percentage
⚡ Common Percentage Quick Reference
Percentage Calculator Guide
What Is a Percentage?
A percentage is a number expressed as a fraction of 100. The word comes from the Latin per centum meaning "per hundred." Percentages are used everywhere — sales discounts, tax rates, interest rates, test scores, tips, and more.
How to Calculate Percentages
| Problem Type | Formula | Example |
|---|---|---|
| X% of Y | Y × (X ÷ 100) | 20% of 150 = 30 |
| X is what % of Y | (X ÷ Y) × 100 | 30 is 20% of 150 |
| % Change | ((New − Old) ÷ Old) × 100 | 100→120 = +20% |
| Add % | Value × (1 + % ÷ 100) | $85 + 15% = $97.75 |
| Subtract % | Value × (1 − % ÷ 100) | $200 − 20% = $160 |
| % Difference | |A−B| ÷ ((A+B)÷2) × 100 | 80 vs 100 = 22.2% |
Common Percentage Shortcuts
- 10% — Move the decimal point one place left (200 → 20)
- 5% — Half of 10% (200 → 10)
- 25% — Divide by 4 (200 → 50)
- 50% — Divide by 2 (200 → 100)
- 75% — Three-quarters (200 → 150)
- 1% — Move decimal two places left (200 → 2)
- Any % — Multiply by (percent ÷ 100)
Real-World Percentage Examples
| Situation | Calculation | Answer |
|---|---|---|
| 15% tip on $60 meal | $60 × 0.15 | $9.00 |
| 25% off $80 shirt | $80 × 0.75 | $60.00 |
| 8.5% sales tax on $120 | $120 × 1.085 | $130.20 |
| Score: 42 out of 50 | (42 ÷ 50) × 100 | 84% |
| Salary raise: $50k → $55k | ((55k−50k)÷50k)×100 | 10% raise |
| Weight loss: 200 lb → 185 lb | ((200−185)÷200)×100 | 7.5% loss |
Percentage vs Percentage Points
These are often confused:
- Percentage change: Interest rate goes from 2% to 3% — that's a 50% increase (doubled by half)
- Percentage points: Interest rate goes from 2% to 3% — that's an increase of 1 percentage point
- Politicians and media often confuse these — always check which one is being used!
Frequently Asked Questions
How do I calculate 20% of a number?
Multiply the number by 0.20 (or divide by 5). Example: 20% of 150 = 150 × 0.20 = 30. Or simply find 10% first (move decimal left) then double it: 10% of 150 = 15, so 20% = 30.
How do I calculate a percentage increase?
Formula: ((New Value − Old Value) ÷ Old Value) × 100. Example: Price goes from $80 to $100. ((100 − 80) ÷ 80) × 100 = 25% increase.
What is the difference between percentage and percent?
Percent (%) is the symbol/unit. Percentage is the general concept. They're used interchangeably in everyday language. "The discount is 20 percent" and "the discount percentage is 20%" both mean the same thing.
How do I calculate a tip?
Multiply the bill by the tip percentage as a decimal. For 15%: bill × 0.15. For 20%: bill × 0.20. Quick trick for 20%: move the decimal left one place (10%) then double it. Example: $85 bill → $8.50 × 2 = $17 tip.
How do I find what percentage one number is of another?
Divide the part by the total and multiply by 100. Example: 45 out of 60 = (45 ÷ 60) × 100 = 75%. This is useful for test scores, survey results, and any ratio.
What is percentage difference vs percentage change?
Percentage change goes from one specific value to another (directional — has a start and end). Percentage difference compares two values without direction, using their average as the base. Use percentage change for before/after comparisons, and percentage difference when neither value is clearly the "original."
💡 Pro Tip: To quickly calculate any percentage in your head — find 1% first (divide by 100), then multiply by the percentage you need. Example: 7% of 300 → 1% = 3 → 7% = 3 × 7 = 21. Works every time! 🧮