How do I work out 20% of a number?

Multiply the number by 0.2, or enter 20 and the number in the first card. For example, 20% of 150 is 30.

Why does percent change show an error when the starting value is 0?

Percent change is measured against the starting value, and division by zero is undefined.

What is the difference between percent and percentage points?

If an interest rate goes from 4% to 6%, it rose by 2 percentage points, but the relative change is +50%.

Percentage calculator: part, change, add and subtract

Four simple percentage calculations whose results update as you type.

What is X% of Y?

Percent, %

Of number

X is what percent of Y?

Number X

Number Y

25%

Percent change from A to B

From (A)

To (B)

25%

Increase

Add / subtract a percentage (results: added / subtracted)

Number X

Percent, %

121 / 79

First number: with the percentage added, second: with it subtracted.

How to use it

Pick the card that matches your question and enter two numbers. The result appears immediately, with no button to press. You can type a decimal comma or point (for example 12,5 or 12.5).

X% of Y: result = X / 100 × Y. For example, 15% of 200 is 30.
X is what percent of Y: result = X / Y × 100. For example, 30 of 120 is 25%.
Percent change: (B − A) / |A| × 100. For example, from 80 to 100 the change is +25%.
Add / subtract a percentage: both results are shown, for example a price with 21% VAT added.

Useful things to know

Percent change is always measured against the starting value. That is why a price that rises 25% and then falls 25% does not return to the start: 100 → 125 → 93.75.

To remove VAT that was added at 21%, divide by 1.21 rather than subtracting 21%. The fourth card subtracts a percentage of the amount you give it, so it does not apply to that case.

Privacy

Everything is calculated in your browser. The numbers you enter are never sent anywhere.