Percentage calculator
Pick the question that matches yours and type two numbers. The answer and the formula appear as you type.
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Runs in your browser. Nothing is uploaded.
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Percentage of a number
What is % of ?
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Type both numbers to see the answer.
What percent is it?
is what % of ?
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Type both numbers to see the answer.
Percentage change
From to is a change of…
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Type both numbers to see the answer.
Add a percentage
Increase by %
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Type both numbers to see the answer.
Remove a percentage
Decrease by %
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Type both numbers to see the answer.
Find the original number
is % of what?
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Type both numbers to see the answer.
How it works
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Find your question
Each box answers one everyday question: a share of a number, a ratio, a change, a price with or without a percentage.
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Type two numbers
Use your usual decimal separator. The result updates on every keystroke, no button to press.
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Check and copy
The formula shows exactly how the answer was found. Copy the result with one click.
Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100, then multiply by the number. For example, 15 % of 80 is 15 ÷ 100 × 80 = 12.
How is percentage change calculated?
Subtract the starting value from the final value, divide by the starting value, then multiply by 100. Going from 50 to 65 is (65 − 50) ÷ 50 × 100 = +30 %. A negative result is a decrease.
Why doesn’t adding 20 % then removing 20 % bring me back to the start?
Because the second percentage applies to a different number. 100 plus 20 % is 120, and 120 minus 20 % is 96. To undo an increase of 20 %, divide by 1.2 instead: that is what “Find the original number” does.
What is the difference between percent and percentage points?
Percentage points measure the gap between two percentages. A rate rising from 2 % to 3 % went up by 1 percentage point, but by 50 % in relative terms.
Can I use commas as decimal separators?
Yes. The calculator reads numbers the way they are written in your language, such as 12,5 or 12.5, and shows the results the same way.
Are my numbers saved or sent anywhere?
No. Every calculation happens in your browser, and nothing is stored once you close the page.