Three of the most common percentage sums in one place. Work out a percentage of a number, find what percentage one number is of another, and calculate the percentage increase or decrease between two numbers. Results update as you type.
How it works
X% of Y = X ÷ 100 × Y.
X is what % of Y = X ÷ Y × 100.
Percentage change = (new value − old value) ÷ old value × 100. A positive result is an increase and a negative result is a decrease.
Worked example
15% of 200 is 30. 30 is 15% of 200. A price that goes from 80 to 100 has risen by (100 − 80) ÷ 80 = 25%.
Tips
- A 50% rise followed by a 50% fall does not return to the start. The base for each percentage is different.
- To add a percentage to a price, multiply by 1 plus the rate. To take it off, multiply by 1 minus the rate.
- For tax, use the VAT calculator and for discounts use the discount calculator.
Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 15% of 200 is 0.15 × 200 = 30.
How do I work out percentage increase?
Subtract the old number from the new one, divide by the old number and multiply by 100.
Why is percentage change not symmetrical?
Because each change is measured against a different starting number.
More free tools: Discount calculator · VAT calculator · All free tools
This calculator is for general guidance only. Check important figures yourself.