Choose your question
Find a percentage of a value, a proportion, a change, or a discounted price.
Percentage calculator
Find a percentage, compare changes, or work out a discount. Choose the calculation you need.
Your result
Enter two values and calculate.
Value × percent ÷ 100
Results are displayed to 12 significant digits. Very large or small values use scientific notation.
How to calculate a percentage
Enter two values
Follow the field labels and example. Negative values work in the mathematical modes; prices and discounts have their own limits.
Calculate and copy
Read the result alongside its formula. Edit either value and calculate again without reloading.
Examples for every mode
X% of a value
15% of 200 = 30. Negative percentages are also allowed.
What percentage?
25 is 12.5% of 200. The whole cannot be zero.
Percentage change
From 100 to 120 is a 20% increase. From 100 to 80 is a 20% decrease.
Price after discount
A price of 1,000 with 10% off saves 100 and leaves 900.
Common questions
How does change work with a negative starting value?
The formula divides by the absolute old value. Moving from −100 to −50 is a 50% increase. A zero starting value has no defined percentage change.
Are results rounded?
Results are displayed to 12 significant digits. Very large or small values use scientific notation. Calculations use JavaScript number precision rather than unlimited decimal precision.
Are my values saved?
Your values stay in this page. They are not saved or uploaded.