How it works
First divide the percentage by 100, then multiply by the original value. For an increase, add that amount to the original; for a decrease, subtract it. For example, 20% of 1,500 is 300.
Inputs and units
| Input | Example value | What to enter |
|---|---|---|
| Value | 1,500 | Enter a numeric value. |
| Percentage (%) | 20 | Enter a numeric value. |
| Operation | Percentage of a value | Check the selected option before calculating. |
Worked example
Show example inputs and results
This example is generated by the same calculation engine using the starting values in the form. Your own inputs produce your own result.
- Value
- 1,500
- Percentage (%)
- 20
- Operation
- Percentage of a value
Complete example results
- Result
- 300
- Percentage amount
- 300
Reading the result
Use quantities on the same basis. The starting value in percentage change, the denominator in a ratio and the length unit in geometry determine the meaning of the answer. Check the formula conditions alongside the example.
Questions and answers
Can I use the example values for my own calculation?
The example values illustrate the calculation. Replace every input with your own information, especially dates, rates and the selected operation.
Does adding 20% undo subtracting 20%?
No. The second percentage acts on a different base: 100 → 80 → 96. To reverse a 20% reduction you need a 25% increase.
Why are some results rounded?
Results display up to 8 decimal places. Calculations use the unrounded values; very small values use scientific notation. JavaScript floating-point arithmetic can introduce tiny rounding differences.
Are my inputs sent to a server?
The calculator processes inputs in your browser. Its code does not send your values to a server.