How to Calculate Percentages — Free Calculator + Formulas
Percentage calculations come up everywhere — shopping, finance, grades, tips, cooking. Here's every formula you need.
Calculate Instantly
Use our Percentage Calculator — three modes, instant results:
- What is X% of Y? — Example: What is 15% of 200? Answer: 30
- X is what % of Y? — Example: 30 is what % of 200? Answer: 15%
- % increase/decrease — From 200 to 250? Answer: 25% increase
The Formulas
X% of Y
Result = (X / 100) × Y
Example: 20% of 150 = (20/100) × 150 = 30
X is what % of Y
Percentage = (X / Y) × 100
Example: 45 is what % of 200? = (45/200) × 100 = 22.5%
Percentage Change
Change = ((New - Old) / Old) × 100
Example: 200 to 250 = ((250-200)/200) × 100 = 25% increase
Common Percentages
| Percentage | As Decimal | As Fraction |
|---|---|---|
| 10% | 0.1 | 1/10 |
| 20% | 0.2 | 1/5 |
| 25% | 0.25 | 1/4 |
| 33.3% | 0.333 | 1/3 |
| 50% | 0.5 | 1/2 |
| 75% | 0.75 | 3/4 |