Percentage Calculator

Six common percentage calculations in one place. Update any input and the result recalculates instantly.

Runs in your browser · No data sent anywhere
What is X% of Y?
% of =
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X is what % of Y?
is what % of =
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Percentage change from X to Y
From to =
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Increase X by Y%
increased by % =
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Decrease X by Y%
decreased by % =
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X% of what number is Y?
% of what number is =
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Frequently Asked Questions

How do I calculate X% of a number?

Multiply the number by X and divide by 100. For 25% of 200: 200 × 25 ÷ 100 = 50.

How do I find the percentage change?

Subtract the old value from the new value, divide by the old value, multiply by 100. Formula: ((new - old) / old) × 100. A positive result is an increase; negative is a decrease.

How do I reverse a percentage (find the original)?

If X% of some number equals Y, then the original number is Y ÷ (X / 100). For example: 25% of what = 50? Answer: 50 ÷ 0.25 = 200.

How do I add a percentage to a number?

Multiply the number by (1 + percentage/100). For 200 + 15%: 200 × 1.15 = 230. To subtract a percentage: 200 × (1 - 0.15) = 170.