Percentage Calculator
Percent of, is-what-percent, and % change.
Runs entirely in your browser — nothing you enter is uploaded or sent to a server.
Simple percentage maths — just make sure you've picked the right question (percent-of, is-what-percent, or change), since each one answers something different. Read our full disclaimer.
About this tool
Percentages come up all day — a discount at the till, a tip, a test score, a growth figure, VAT or GST on a price. This tool handles the three questions people actually ask, in one place: what is X% of a number, what percentage one number is of another, and the percentage change from one value to another. Enter the two numbers and the answer appears instantly, with the working shown so you can see how it was reached — all in your browser.
Try it
15% of 200 is 30. 30 is 15% of 200. Going from 200 to 250 is a 25% increase.
How to use
- 1Pick the type of question.
- 2Enter the two numbers.
- 3Read the answer instantly.
Features
- Three questions in one: percent-of, is-what-percent, and % change.
- Handles both increases and decreases (signed % change).
- Answers update the moment you type the two numbers.
Frequently asked questions
How do I find X% of a number?
Multiply the number by the percentage written as a decimal: X% of Y = (X ÷ 100) × Y. For example, 15% of 200 is 0.15 × 200 = 30. The 'percent of' mode does this for you.
How do I work out what percentage one number is of another?
Divide the part by the whole and multiply by 100: X is (X ÷ Y) × 100 percent of Y. So 30 out of 200 is (30 ÷ 200) × 100 = 15%. Use the 'is what percent' mode.
How do I calculate percentage change?
Percentage change = (new − old) ÷ |old| × 100. From 200 to 250 that's (250 − 200) ÷ 200 × 100 = a 25% increase; a drop to 150 would be −25%. The 'percent change' mode signs it for you.
How do I work out a discount or percent off?
A price with X% off is the original minus X% of it. Use 'percent of' to get the discount, then subtract: £50 with 20% off is 50 − (0.20 × 50) = £40.
What's the difference between percentage points and percent?
Going from 10% to 15% is a rise of 5 percentage points, but a 50% increase (15 is 1.5× of 10). This tool works in percent — convert to points yourself when you're comparing two percentages directly.
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