Percentage Calculator
Quick answer: A percentage is a number out of 100. To find X% of Y, multiply Y by X and divide by 100. For example, 15% of 240 is 36. This calculator also works out percentage change and what percent one number is of another.
Use the Percentage Calculator
Percentage formula and what each symbol means
X% of Y = X ÷ 100 × Y. Percent of total = part ÷ whole × 100. Percentage change = (new − old) ÷ old × 100.
| Symbol | Meaning |
|---|---|
| X | The percentage |
| Y | The whole amount |
| old / new | Starting and ending values |
Percentage examples
Percent of a number
15% of 240 = 15 ÷ 100 × 240 = 36.
Percent change
A price rises from 80 to 100. Change = (100 − 80) ÷ 80 × 100 = 25% increase.
What percent
45 is what percent of 180? 45 ÷ 180 × 100 = 25%.
How to calculate Percentage step by step
- Decide which question you are answering: percent of, percent change or what percent.
- Put the numbers in the matching formula.
- Divide first, then multiply by 100 for a percent.
How to read your Percentage result
A fall from 100 to 80 is 20%, but a rise from 80 back to 100 is 25%. Percent change depends on the starting value.
Common mistakes when calculating Percentage
- Dividing by the new value instead of the old value for change.
- Adding and subtracting percentages of different bases.
- Confusing percentage points with percent.
Percentage FAQ
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. 20% of 50 is 20 × 50 ÷ 100 = 10.
How do I calculate percentage increase?
Subtract the old value from the new one, divide by the old value, and multiply by 100.
What is the difference between percent and percentage points?
If a rate goes from 10% to 12%, it rises 2 percentage points, but the relative increase is 20%.
How do I reverse a percentage change?
Divide by (1 + rate). To undo a 25% rise, divide by 1.25, which is the same as taking off 20% of the new value.
Method, review and disclaimer
Edited by: Hemant Kumar and Anjita Rai, founders of ToolsVault (SEO and content professional, not a licensed adviser). Method: this tool runs in your browser using the formula shown on this page; the numbers you enter are not sent to our servers.