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Percentage calculator

Three everyday percentage questions, answered as you type.

Runs in your browser · Nothing uploadedFree · No install

Percentage calculator

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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How to use

  1. 1Pick the question that matches what you want to know.
  2. 2Type the two numbers. Commas and decimal points both work.
  3. 3Read the answer right below the fields.

About this tool

Three percentage questions

  • X% of Y: multiply Y by X and divide by 100. 15% of 200 is 30.
  • X is what percent of Y: divide X by Y and multiply by 100. 30 is 15% of 200.
  • Percentage change from X to Y: (Y − X) ÷ |X| × 100. From 100 to 120 is +20%; from 120 to 90 is −25%.

Percent vs. percentage points

If an interest rate goes from 2% to 3%, it rose by 1 percentage point but by 50 percent. News and bank documents often mix these up; the change form gives the percent change, so enter 2 and 3 to see +50%.

Typing numbers

You can type thousands separators and decimals the way you are used to: 1,250.5 and 1250.5 both work, and so does a comma as the decimal point (0,125). Spaces are ignored.

Results are rounded to 15 significant digits, so 0.1 → 0.3 shows +200% rather than 199.99999999999997%.

When there is no answer

A percentage change from 0 and “what percent of 0” would mean dividing by zero, so the calculator says it cannot calculate instead of showing infinity. Empty fields simply show a dash.

Frequently asked questions

How do I calculate a discount?

Use “What is X% of Y” with the price and the discount rate to get the amount saved, then subtract it from the price.

How do I work out a percentage increase?

Use the change form: enter the old value in From and the new value in To. A positive result is an increase, a negative one a decrease.

Why is the change from 0 not calculated?

Any change from zero is an infinite percentage, so there is no meaningful answer.

Can I use decimals and negative numbers?

Yes. Decimals with a point or a comma, and negative numbers with a leading minus sign, are all accepted.

Are my numbers saved?

No. Everything is calculated in your browser while you type; nothing is stored or sent.

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