Percentage Calculator
Three percentage calculations in one tool: find X% of a number, find what percent one number is of another, or calculate the percent change between two values.
Operated by: Cloudtopia Maintenance: Updated when formulas, supplier packaging, or guidance change.
Enter values — result updates instantly.
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The Three Formulas
1. What is X% of Y?
Result = (X / 100) × Y
Example: What is 15% of 200? → (15/100) × 200 = 30
2. X is what percent of Y?
Percent = (X / Y) × 100
Example: 30 is what percent of 200? → (30/200) × 100 = 15%
3. Percent change from X to Y
% Change = ((New − Old) / |Old|) × 100
Example: Change from 50 to 75? → ((75−50)/50) × 100 = 50%
Common Percentage Equivalences
| Fraction | Decimal | Percentage |
|---|---|---|
| 1/4 | 0.25 | 25% |
| 1/3 | 0.333 | 33.3% |
| 1/2 | 0.50 | 50% |
| 2/3 | 0.667 | 66.7% |
| 3/4 | 0.75 | 75% |
Practical Uses
Percentage calculations come up everywhere: figuring out a tip, calculating discounts, understanding material waste factors (add 10% for waste), comparing price changes, and determining how much of your budget a project component uses. The percentage change mode is especially useful for comparing quotes from different suppliers.