DigiTools

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Percentage calculator

Five quick percentage calculators in one place: percent of a number, what percent one number is of another, percentage change and more. Each one shows its working.

What is X% of Y?

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X is what percent of Y?

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Percentage change from X to Y

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X is Y% of what?

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Increase or decrease X by Y%

Change

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What you type stays on this device. Nothing is uploaded.

How to calculate a percentage

  1. Find the calculator that matches your question.
  2. Type your two numbers. The answer appears as you type.
  3. Check the formula under the answer to see how it was worked out.

Questions

Are my numbers sent anywhere?

No. The calculator works in your browser on this device. Your numbers are never uploaded or stored, and they’re gone when you close the page.

How do I work out a percentage of a number?

Divide the percentage by 100 and multiply by the number. For example, 20% of 150 is 0.2 × 150 = 30.

How is percentage change worked out?

Take the old value from the new one, divide by the old value and multiply by 100. Going from 200 to 250 is (250 − 200) ÷ 200 × 100, a 25% increase. A negative result is a decrease. Answers are rounded to 4 decimal places.

Why doesn’t a 10% rise and then a 10% fall get me back to the start?

Because the second percentage is of a different number. 100 plus 10% is 110, and 110 minus 10% is 99. To undo a 10% rise, take off about 9.09%.