How to Calculate Percentages: 3 Types Explained Simply
There are 3 main percentage calculations: X% of a number, what percent X is of Y, and percentage change. Here's each one with examples.
Type 1: What Is X% of a Number?
(percentage / 100) x number
Example: 15% of 80 = 0.15 x 80 = 12
Mental shortcut: 10% = move decimal left. 10% of 80 = 8. 20% = double. 5% = halve.
Type 2: X is What % of Y?
(X / Y) x 100
Example: 30 is what percent of 120? (30/120) x 100 = 25%
Type 3: Percentage Change
((New - Old) / Old) x 100
Example: $40 to $50 = ((50-40)/40) x 100 = 25% increase
Quick Reference
| Question | Formula | Example |
|---|---|---|
| X% of Y | (X/100) x Y | 15% of 200 = 30 |
| X is what % of Y | (X/Y) x 100 | 30 of 200 = 15% |
| % change X to Y | ((Y-X)/X) x 100 | 200 to 250 = +25% |
Common Equivalents
| Percentage | Decimal | Fraction |
|---|---|---|
| 10% | 0.10 | 1/10 |
| 25% | 0.25 | 1/4 |
| 50% | 0.50 | 1/2 |
| 75% | 0.75 | 3/4 |
| 100% | 1.00 | 1/1 |
Calculate any percentage instantly — all three types in one tool.
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