Free online tool
Percentage Calculator
Solve the most common percentage questions with one calculator and see the equation used for each result.
Method
Percentage formulas
A percentage is a ratio per hundred. Converting the percentage to a decimal before multiplication keeps the operation explicit.
Percentage change uses the original value as its denominator. A zero original value therefore has no finite percentage change.
Questions
Percentage Calculator FAQ
How do I calculate a percentage of a number?
Divide the percentage by 100, then multiply by the number. For example, 15% of 80 is 0.15 x 80 = 12.
How do I find the original amount before a percentage?
Divide the final amount by one plus or minus the percentage rate expressed as a decimal, depending on whether it increased or decreased.
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