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Percentage Calculator

Updated June 2026 · By the NumberBench editorial team · How we calculate

Three percentage questions in one tool. Pick a mode and enter two numbers to get the answer instantly.

Result—

Proportion

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The three common questions

Percent of: 10% of 200 is 20. Is what percent: 20 out of 200 is 10%. Percent change: going from 200 to 220 is a 10% increase, and a drop to 180 is a 10% decrease. Switch modes above to answer whichever you have.

How it’s calculated

Percent of: A ÷ 100 × B. Is what percent: A ÷ B × 100. Change: (B − A) ÷ A × 100.

Results update as you type and are estimates, not professional advice — verify important decisions with a qualified professional.

Worked example

10% of 200 is 20; 20 is 10% of 200; going 200 to 220 is a 10% increase.

Common mistakes

  • Confusing percentage points with percent change.
  • Reversing which number is the base.

Where it is used

  • Working out a percent of a number.
  • Finding a percent change between two values.

Frequently asked questions

How do I find a percentage of a number?

Multiply the number by the percent and divide by 100. 15% of 80 = 80 × 15 / 100 = 12.

How is percent change calculated?

(New − Old) / Old × 100. Negative results mean a decrease.

Percentage points vs. percent?

Going from 10% to 12% is a 2 percentage-point rise but a 20% relative increase — they're different things.