Math and measurement tools
Percentage Calculator
Find a percentage of a number, percentage change, or an amount after an increase or discount. Clear formulas, examples and private printable results.
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How to use this tool
1. Choose the question you want to answer. Only the two inputs for that calculation are shown.
2. Enter non-negative numbers. A whole or original value used as a divisor must be greater than zero.
3. Calculate, check the formula and copy or print your result. Changing inputs marks an earlier result as out of date.
How the calculations work
A percentage is a proportion out of 100. A share is part ÷ whole × 100. Relative change is (new − original) ÷ original × 100. An adjusted amount multiplies the original by 1 plus or minus the rate divided by 100.
Worked examples
15% of 240 is 36. A change from 80 to 100 is a 25% increase; reversing those values gives a 20% decrease. Reducing 80 by 25% gives 60.
Questions and assumptions
Percentages versus percentage points
Moving from 20% to 25% is a rise of 5 percentage points and a relative increase of 25%. This tool calculates relative change, not the symmetric percentage difference between two observations.
Scope and precision
Use non-negative values up to 1,000,000 with up to six decimal places. Decreases are limited to 100%. Results use up to twelve significant digits; this is general arithmetic and does not apply tax, interest periods or currency rounding rules.
Sources and further reading
Built and maintained by Custom Logic. Page updated .