Percentage Calculator

X% of Y, or what % one number is of another.

Calculate a percentage of a number, what percent one number is of another, or the percent change between two numbers.

How it works

Three common calculations: X% of Y = Y × X / 100; X is what percent of Y = X / Y × 100; and percent change = (new − old) / old × 100.

When it helps

Useful for discounts, grades, tax, tips, statistics and tracking growth.

Worked examples for each mode

% of a number: 15% of 240 is 240 × 15 / 100 = 36. This is how you work out a tip, a tax amount or a commission. X is what % of Y: if you scored 45 out of 60, that's 45 / 60 × 100 = 75%. % change: a price rising from 80 to 100 is (100 − 80) / 80 × 100 = +25%, and falling from 100 to 80 is −20%.

Notice that the same 20-unit difference gives 25% one way and 20% the other. Percent change always depends on the starting value.

Mistakes to avoid

Adding percentages that apply one after another gives the wrong answer — two 10% rises add up to 21%, not 20%. And a percentage of a percentage needs care: '20% of the 30% who answered' is 6% of everyone.

When you read a headline about a big percentage increase, check the starting number. Going from 1 case to 3 is a 200% rise, but it's still only 3 cases.

Frequently asked questions

Why isn't a 50% rise followed by a 50% fall back to the start?

The fall applies to the larger number. 100 → 150 → 75.

What's the difference between percent and percentage points?

Going from 10% to 12% is a 2 percentage-point rise, but a 20% relative increase.

How do I add VAT to a price?

Multiply by 1 plus the rate. For 20% VAT, 50 × 1.2 = 60. To remove it, divide: 60 / 1.2 = 50.

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