Free, private, shows the working
Percentage calculator
Work out a percent of a number, what percent one number is of another, or raise and lower a value by a percent. The calculation is shown so you can check it.
Calculated in your browser. Nothing you enter is sent or saved.
To find a percent of a number, multiply the number by the percent and divide by 100. To find what percent X is of Y, divide X by Y and multiply by 100. To increase a number by a percent, multiply it by 1 plus the percent over 100.
Every common calculation
Percent of a number, one number as a percent of another, increase and decrease, plus separate pages for percentage change, discounts and reverse percentages.
Shows the working
Each result comes with the formula and the numbers filled in, so you can check it or copy the method.
Exact and private
Results are free from floating point rounding errors, and everything is calculated in your browser. Nothing you type is sent.
More calculators
Guides
- How to calculate percentagesThe four calculations, with worked examples.
- Percent vs percentage pointsWhy 4% to 6% is both "2 points" and "50% more".
- Why a rise and a fall do not cancelThe base changes, so the result does not return.
- How our percentage calculator worksFormulas, rounding and privacy, step by step.
Check the base value
Most percentage mistakes come from using the wrong base. A 20% increase is 20% of the old value, and a 20% decrease is 20% of the new starting value, which is why a rise and a fall of the same percent do not cancel out. See why they do not cancel.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percent, then divide by 100. For example, 15% of 200 is 15 x 200 / 100 = 30.
How do I find what percent one number is of another?
Divide the first number by the second and multiply by 100. For example, 30 is 30 / 200 x 100 = 15% of 200.
How do I increase a number by a percent?
Multiply the number by 1 plus the percent divided by 100. To raise 80 by 25%, calculate 80 x 1.25 = 100. To decrease it by 25%, calculate 80 x 0.75 = 60.
How do I calculate percentage change?
Subtract the old value from the new value, divide by the old value and multiply by 100. See the percentage change calculator.
Are my numbers saved?
No. Everything is calculated in your browser and nothing is sent or stored.