Percentage Calculator
Math & EverydaySolve percentage of, percentage change and reverse percentages.
Runs entirely in your browser — nothing is uploaded
What people do next
Features
- Four modes: X% of Y, X is what % of Y, percentage change, and reverse percentage.
- Shows the working, not just the answer.
- Handles increases and decreases with the correct sign.
- Rounding control for clean results.
How to use the Percentage Calculator
- 1Choose the type of percentage question.
- 2Fill in the two known numbers.
- 3Read the answer along with the formula used.
Frequently asked questions
Why is a 50% rise then a 50% fall not break-even?
The fall applies to the larger number. 100 → 150 → 75. To undo a 50% rise you need a 33.3% fall.
What is a reverse percentage and when do I need one?
It works backwards from a figure that already contains the change. If something costs 590 including 18% tax, the amount before tax is 590 divided by 1.18, not 590 minus 18%. Subtracting the percentage from the final figure is the commonest percentage error there is, and it always produces a number that is too small.
How do I work out percentage change from zero?
You cannot, and no tool should pretend otherwise. There is no base to compare against, so going from 0 to 50 is not an infinite increase, it is simply an increase of 50. Report the absolute change in that case.
What is the difference between percent and percentage points?
If a rate moves from 4% to 6%, that is a rise of two percentage points and also a rise of fifty percent. Both describe the same movement and both are correct, which is precisely why the ambiguity gets used: up 50% sounds far more dramatic than up 2 points.