Percentage Calculator

Calculate any percentage in seconds with five built-in modes. Find X% of a number, work out what percent one value is of another, measure the percentage increase or decrease between two figures, find the whole from a known part, or add and subtract a percentage from a value. Each mode shows the exact formula used and updates the moment you type — all in your browser, with no sign-up and nothing sent to a server.

Find how much a percentage of a number is — e.g. 20% of 150.

Percentage (X) *

Of value (Y) *

Your result will appear here

Enter the values above to calculate instantly.

How to use

Pick the calculation you need from the five tabs.
Enter the two values — the result and formula appear instantly as you type.
For percentage change, enter the old value (A) and the new value (B) to see the increase or decrease.
For add / subtract, enter a value and a percentage to see both the higher and lower result at once.
Click Copy result to paste the figure into a document, message or spreadsheet.

Features

Find X% of any number, with the working shown
Work out what percentage one value is of another
Percentage increase or decrease between two values, with the difference
Reverse percentage: find the whole (100%) from a known part
Add or subtract a percentage and see both results together
100% in-browser — locale-tolerant input and instant results

Frequently asked questions

How do I calculate a percentage of a number?

Multiply the number by the percentage and divide by 100. For example, 20% of 150 is 150 × 20 ÷ 100 = 30. Use the "X% of Y" tab and the calculator shows both the answer and the formula.

How do I work out what percentage one number is of another?

Divide the part by the whole and multiply by 100. For example, 30 out of 150 is 30 ÷ 150 × 100 = 20%. The "X is what % of Y" tab does this for you instantly.

How do I calculate percentage increase or decrease?

Subtract the old value from the new value, divide by the old value, then multiply by 100. Going from 150 to 180 is (180 − 150) ÷ 150 × 100 = 20% increase. A negative result means a decrease.

How do I find the original number before a percentage?

Divide the known part by its percentage and multiply by 100. If 30 is 20% of a number, the whole is 30 ÷ 20 × 100 = 150. Use the "Find the whole" tab for this reverse calculation.

Is this percentage calculator free?

Yes, it is completely free with no sign-up. Everything runs in your browser, so your numbers are never uploaded or stored anywhere.

Percentage Calculator

How to use

Features

Frequently asked questions

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