Percentage Calculator

Choose what you want to work out, enter two numbers, and press Calculate. Six kinds of percentage problem are covered, from 25% of 200 to the change between two prices, and each answer comes with the formula and every step.

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About this percentage calculator

Percent means per hundred, so 25% is 25 out of every 100. Percentages turn up in discounts, tips, tax, test scores, interest, and statistics, but each kind of question needs a slightly different formula. This calculator covers the six you meet most often: finding a percentage of a number, finding what percent one number is of another, the percentage change from an old value to a new one, the percentage difference between two values, and increasing or decreasing a number by a percentage. Every answer shows the formula and the numbers plugged into it, so you can check or learn the method.

How to calculate a percentage

  1. Choose the question. Pick the kind of calculation, such as What is X% of Y? The labels on the two boxes change to match.
  2. Enter the numbers. Type the two values, or press an example such as 15% tip on $85.
  3. Press Calculate. Read the answer, the percentage bar, and the steps used to get there.

Frequently asked questions

How do I find a percentage of a number?

Divide the percentage by 100 and multiply by the number. 15% of 85 is 0.15 × 85 = 12.75. A quick check: 10% is the number divided by 10, and 5% is half of that.

What is the difference between percentage change and percentage difference?

Percentage change has a direction: it compares a new value with an old one, so going from 80 to 60 is −25%. Percentage difference compares two values on equal terms, dividing by their average, so 80 and 60 differ by about 28.6%.

Why does a 30% discount followed by a 30% increase not get back to the start?

The increase is calculated on the lower price. 120 minus 30% is 84, and 84 plus 30% is 109.20, not 120. To undo a 30% decrease you need an increase of about 42.9%.

How do I work out what percent a score is?

Choose X is what percent of Y, enter your score as X and the maximum as Y. 42 out of 50 is 42 ÷ 50 × 100 = 84%.

Can I use negative numbers or decimals?

Yes. Both boxes accept decimals and negative values. Percentage change uses the absolute value of the starting number, so the sign of the result always shows whether the value went up or down.