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Percentage Calculator

Work out X% of a number, what percent one number is of another, percentage change, and increases or decreases.

100% Client-Side

Fill in any of the calculators below — each result updates as you type and shows the formula used.

How to use the Percentage Calculator

  1. 1

    Pick the question you need answered, like "What is X% of Y?" or "Percentage change".

  2. 2

    Type the numbers into that row.

  3. 3

    Read the result, along with the formula that produced it.

  4. 4

    Copy the answer, or adjust the numbers to try other scenarios.

Frequently asked questions

Subtract the old value from the new value, divide by the old value and multiply by 100. Going from 80 to 100 is (100 − 80) ÷ 80 × 100 = 25% increase.

Use "Decrease by %": enter the price and the discount. A 20% discount on 50 is 50 × (1 − 0.20) = 40. The "X% of Y" row tells you the amount saved (10).

Because the second percentage applies to a different base. 100 + 10% is 110, and 110 − 10% is 99. Percentage changes multiply rather than add.

Percentage change and "X is what percent of Y" divide by that value, and dividing by zero is undefined, so no result is shown until you enter a non-zero number.

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