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Percentage calculator
Calculate a percentage of a value, a share, percentage change, increases, decreases and the original whole. Review and copy both the result and its formula.
Result
This tool does not send entered values or selected files to a server. Save any results you need before closing the tab.
How to use
- Choose a calculation type. For B% of A, B is a percentage; for percentage change, B is the new value.
- Enter A and B using consistent units. Negative values are accepted.
- Generate the result, check that the displayed formula matches your intention, then copy it.
Worked example
15% of 200 is 30. A change from 200 to 230 is a 15% increase. A rate moving from 15% to 20% rises by 5 percentage points.
Method and limitations
Part=A×B÷100; share=B÷A×100; change=(B−A)÷|A|×100. Increase or decrease multiplies A by (1±B÷100). If A represents B%, the whole is A÷B×100.
Calculations with a zero denominator are rejected. Results use JavaScript floating-point arithmetic and display up to 10 decimal places. Changes from negative baselines divide by the absolute baseline.
Frequently asked questions
How do percent and percentage points differ?
A rate rising from 20% to 25% gains 5 percentage points, but its relative increase is 25%. Choose percentage change with A=20 and B=25 to check.