Percentages appear in discounts, exam marks, salary hikes, interest rates and business reports. The maths is simple once you know which of four questions you are asking.
Try it now: Percentage Calculator
Free, no sign up, and the file stays on your device.
Open Percentage CalculatorWhat is X% of Y?
Multiply Y by X and divide by 100. 20% of 150 is 150 x 20 / 100 = 30. This is the calculation behind a 20% discount on a 150 rupee item.
X is what percent of Y?
Divide X by Y and multiply by 100. If you scored 42 out of 60, then 42 / 60 x 100 = 70%.
Percentage increase or decrease
Subtract the old value from the new one, divide by the old value and multiply by 100. A price that goes from 50 to 75 has risen by (75 - 50) / 50 x 100 = 50%.
Adding and subtracting a percent
- To add 18% to 1,000, multiply by 1.18 to get 1,180.
- To take 18% off 1,000, multiply by 0.82 to get 820.
- To find the original price after a discount, divide the sale price by (1 - discount).
A common trap
A 50% rise followed by a 50% fall does not return to the start. 100 becomes 150 and then 75. Each change uses a different base, so percent changes cannot simply be added together.
Frequently asked questions
How do I find a discount percentage?
Subtract the sale price from the original price, divide by the original price and multiply by 100.
What is the difference between percent and percentage points?
Going from 10% to 12% is a rise of 2 percentage points, but a 20% increase in the rate itself.
Is my data stored?
No. The calculation happens in your browser.
Ready to start?
Open Percentage Calculator