Percentage Calculator

Three percentage tools in one: what is X% of Y, X is what percent of Y, and percentage increase or decrease from one number to another — with the working shown.

What do you want to find?

The three everyday percentage problems

Almost every percentage question is one of these three, and this calculator covers them all:

Worked examples

15% of 240 = 240 × 0.15 = 36 (a 15% tip on a 240 bill). 45 of 60 = 45 ÷ 60 × 100 = 75% (a test score). From 80 to 100 = (100 − 80) ÷ 80 × 100 = +25% (a price increase).

A common trap

Percentage change is measured against the starting value, so a 25% rise followed by a 25% fall does not return to the start: 80 → 100 → 75. When reversing a change, the percentages are never simply equal and opposite.

Frequently asked questions

How do I calculate X% of a number?
Multiply the number by the percentage and divide by 100. For example, 15% of 240 = 240 × 15 ÷ 100 = 36.
How do I work out what percent one number is of another?
Divide the part by the whole and multiply by 100. For example, 45 out of 60 = 45 ÷ 60 × 100 = 75%.
How is percentage increase or decrease calculated?
Percentage change = (new − old) ÷ old × 100. Going from 80 to 100 is (100 − 80) ÷ 80 × 100 = +25%; going from 100 to 80 is −20%. Note the two are not symmetric because the base changes.
Can a percentage be more than 100?
Yes. 150% of 40 is 60, and growing from 20 to 70 is a 250% increase. Over 100% simply means more than the whole original amount.

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