Percentage Calculator
Three common percentage calculations: percent of a number, ratio, and percent change.
What is X% of YX is what % of YPercent change
15% of 200 is
Ad slot (below results · replace with network code)
Percentage Formulas
- Percent of a number: X% of Y = Y × X ÷ 100.
- Ratio (part of a whole): X is what % of Y = X ÷ Y × 100%.
- Percent change: from A to B = (B − A) ÷ A × 100% — positive is an increase, negative is a decrease.
Worked Examples
| Question | Calculation | Answer |
|---|---|---|
| What is 15% of 200? | 200 × 15 ÷ 100 | 30 |
| 25 is what % of 200? | 25 ÷ 200 × 100 | 12.5% |
| Change from 100 to 125? | (125 − 100) ÷ 100 × 100 | +25% |
Results update in real time as you type — no need to press a calculate button.
Frequently Asked Questions
- How do I find X% of a number?
- Multiply the number by the percent and divide by 100. For example, 15% of 200 = 200 × 15 ÷ 100 = 30.
- How do I find what percent one number is of another?
- Divide the part by the whole and multiply by 100. For example, 25 out of 200 = 25 ÷ 200 × 100 = 12.5%.
- How do I calculate percent change?
- Percent change = (new value − old value) ÷ old value × 100. A positive result is an increase; a negative result is a decrease. From 100 to 125 is a 25% increase.
- What is the difference between percent change and percentage points?
- Percent change is relative to the starting value. Percentage points are the simple arithmetic difference between two percentages — going from 10% to 12% is a 2 percentage-point rise but a 20% increase.
📅 Last updated: June 2026 · Formulas follow standard banking / tax conventions · Results are for reference only.