Free tool
Percentage Calculator: Percent of a Number, Percent Change and More
Four percentage calculations in one place, each with the formula so you can see how the answer is worked out.
Runs in your browser: we don’t send or store what you type.
The four percentage formulas you’ll use most
| What you want | Formula | Example |
|---|---|---|
| X% of a number | number × X ÷ 100 | 15% of 240 = 240 × 15 ÷ 100 = 36 |
| What % A is of B | A ÷ B × 100 | 45 of 180 = 45 ÷ 180 × 100 = 25% |
| Percent change from A to B | (B − A) ÷ A × 100 | 80 to 100 = 20 ÷ 80 × 100 = +25% |
| Add or subtract a % | number × (1 ± X ÷ 100) | 500 + 8% = 500 × 1.08 = 540 |
A common mistake: up 20%, then down 20%
A price that rises 20% and then falls 20% doesn’t return to where it started: 100 × 1.20 = 120, then 120 × 0.80 = 96. The second percentage applies to a different base.
Tip For store sales, the discount calculator handles stacked discounts; for tax, use the sales tax calculator.
FAQ
How do I find a percentage of a number?
Multiply the number by the percentage and divide by 100. 30% of 150 = 150 × 30 ÷ 100 = 45.
How do I find what percent one number is of another?
Divide the part by the whole and multiply by 100. 18 out of 60 is 30%.
How do I calculate percent increase?
Subtract the old value from the new one, divide by the old value and multiply by 100. 200 to 250 is a 25% increase.
If something goes up 10% and down 10%, is it the same?
No. 100 rises to 110, and 10% of 110 is 11, so it falls to 99.
