About the percentage calculator
Percentages come up everywhere — discounts, grades, price changes, and statistics. Choose the question you’re asking, enter two numbers, and the answer appears instantly along with the formula, so you can check the math or learn the method.
How to use this calculator
- Choose what you want to find.
- Enter A and B.
- Read the answer and formula.
Worked examples
- 15% of 80 = 0.15 × 80 = 12
- 12 is what % of 80? 12 ÷ 80 × 100 = 15%
- From 50 to 75: (75 − 50) ÷ 50 × 100 = +50%
12; 15%; a 50% increase.
Measurement guidance
Percent vs. percentage points
A rate rising from 4% to 5% is a 1 percentage-point increase, but a 25% relative increase.
Frequently asked questions
Why doesn’t a 50% drop undo a 50% rise?
Each change uses a different base. 100 up 50% is 150; 150 down 50% is 75.
Can A or B be negative?
Yes. Percent change uses the absolute value of the starting number.
How do I calculate a discount?
Use the Discount & Sales Tax Calculator for prices.