Percentage Calculator
Four everyday percentage sums in one place: a percent of a number, one number as a percent of another, percentage change, and adding or taking off a percentage.
What is X% of Y?
X is what percent of Y?
Percentage change from X to Y
Add or take off a percentage
Runs entirely in your browser. Nothing you enter is sent to a server.
How to calculate percentages
Pick the question
Each card answers one kind of question. Use whichever matches what you want to know.
Enter two numbers
Type the values; decimals with a point or a comma both work.
Copy the answer
The result updates as you type, with a sentence that spells it out. Use Copy to take the number.
Percentage change and percentage points
Going from 4% to 5% is a change of one percentage point, but an increase of 25%. The change card works on the values you enter, so enter 4 and 5 to see the 25%.
Why +20% and then −20% isn't zero
Percentages work on the current value. 100 plus 20% is 120; 120 minus 20% is 96. To undo an increase, divide by 1 plus the rate instead.
Frequently asked questions
How do I work out X% of a number?
Multiply the number by the percentage and divide by 100: 15% of 200 is 200 × 15 / 100 = 30.
How is percentage change calculated?
Subtract the old value from the new one, divide by the old value and multiply by 100. From 80 to 100 is (100 − 80) / 80 × 100 = 25%.
Can I use negative numbers?
Yes. Change is measured against the size of the starting value, so going from −50 to −25 counts as an increase of 50%.