Calculate percentages three ways: percent of a number, what percent X is of Y, and percentage increase or decrease. Free and instant.
Last updated 23 June 2026 · Built and maintained by Mustafa Bilgic
This percentage calculator solves the three questions people ask most: finding a percent of a number, working out what percent one value is of another, and measuring percentage change between two numbers. Enter your figures and get an instant, accurate answer.
| Question | Formula |
|---|---|
| X% of Y | (X / 100) x Y |
| X is what % of Y | (X / Y) x 100 |
| % change from A to B | ((B - A) / A) x 100 |
Divide the percentage by 100 and multiply by the number. For example, 20% of 150 is (20 / 100) x 150 = 30. The first calculator does this for you.
Divide the first number by the second and multiply by 100. For example, 30 out of 120 is (30 / 120) x 100 = 25%.
Subtract the old value from the new value, divide by the old value, and multiply by 100. A positive result is an increase; a negative result is a decrease.
Yes. All three calculators accept decimal and negative inputs, and results are rounded to two decimal places for readability.
Yes, it is free with no sign-up and runs entirely in your browser, so calculations are instant and private.