Percentage Calculator

Work out a percentage of a number, a percentage increase or decrease, or a reverse percentage, with each step shown. Ask something like “what is 18% of 250?” and see exactly how the answer is built.

Try an example:

How the Percentage Calculator works

  1. Turn the percent into a decimal or fraction (18% = 0.18 = 18/100).
  2. Multiply it by the number, or use (new − old) ÷ old × 100 for percent change.
  3. Check that the result makes sense: 18% of 250 should be a bit under a fifth of 250.

Frequently asked questions

How do I calculate a percentage of a number?

Divide the percentage by 100 and multiply by the number. For 18% of 250 that is 0.18 × 250 = 45.

How do I find percentage change?

Subtract the old value from the new one, divide by the old value, then multiply by 100. A positive result is an increase, a negative one a decrease.

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MathMate can make mistakes. Please double-check important steps and calculations.