How this calculator works
Calculate percentages, percent change, and reverse percentages instantly with this free online tool. Values are processed instantly on this device, with checks for missing values and invalid divisions.
Percentage Of: (part / whole) * 100 | X Percent Of Y: (x / 100) * y | Percent Change: ((new - old) / old) * 100 | Reverse Percentage: part / (percent / 100)
Worked example
Enter realistic values in each labeled field, select Calculate, and review both the primary answer and supporting details. Use Reset to clear the form before trying another scenario.
Frequently asked questions
What does the Percentage Calculator do?
Calculate percentages, percent change, and reverse percentages instantly with this free online tool.
Are my values stored?
No. The calculation runs locally in your browser and the values are not submitted to us.
Can I rely on this result?
Use this as an informational estimate. Check measurements and source values before acting on the result.