Calculate a sale discount
Twenty-five percent of 80 is (25 / 100) × 80 = 20, so subtracting the discount gives a sale price of 60.
Four percentage calculators in one
Percentage calculator
Answer the four percentage questions people use most, then see the formula and calculation behind the result.
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Formula and steps included
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Formula
Percentage formulas for four common questions
Percent of a number: result = (percent / 100) × number; What percent: percent = (part / whole) × 100; Percent change: change = ((new − original) / |original|) × 100; Reverse percentage: original = final / (1 ± percent/100), using + for an increase and − for a decrease
Percent means per hundred. Converting a percentage to a decimal by dividing by 100 lets you multiply, divide, and compare values consistently.
The correct formula depends on which value is unknown. The calculator separates the four common forms so the labels match the question you are trying to answer.
How to use the formula
Find a percent of a number
Divide the percent by 100, then multiply that decimal by the number.
Find what percent one number is of another
Divide the part by the whole and multiply the result by 100.
Reverse a percentage change
Divide the final value by 1 + percent / 100 after an increase, or by 1 − percent / 100 after a decrease.
Measure percentage change
Subtract the original value from the new value, divide by the absolute value of the original, and multiply by 100. A negative result is a decrease.
Worked examples
Percentage calculator examples
Recover a value before an increase
If a value is 90 after a 20% increase, the original is 90 / (1 + 20 / 100) = 90 / 1.2 = 75.
Common questions
Percentage calculator FAQ
Which percentage calculator should I use?
Use percent of a number for questions like 15% of 60. Use what percent when comparing a part with a whole, percent change when comparing an old value with a new one, and reverse percentage when a final value and its increase or decrease are known.
What is the difference between percent change and percentage-point change?
Percent change measures the change relative to the original value. Percentage-point change is simple subtraction between two percentages, such as 40% to 45% being a 5-point increase.
Why can some percentage calculations not use zero?
What-percent and percent-change formulas divide by the whole or original value, so that value cannot be zero. A 100% decrease cannot be reversed to one unique original value because its change factor is zero.
Are my percentage values uploaded or saved?
Your values are not saved by default or uploaded. You can opt into Remember on this device or download a local JSON backup.