Formula and calculation method
Percent error = |observed − accepted| / |accepted| × 100.
Use consistent units for all comparable inputs. The displayed result is rounded; arithmetic is performed with the full available numeric precision. Check your source measurements before relying on the result.
How to use percent error calculator
- Set Observed value. The example below uses 98.
- Set Accepted value. The example below uses 100.
- Select Calculate to update the result. Reset restores the illustrated inputs. Copy, print or download your own result if you need a record.
Worked example
Example inputs
- Observed value
- 98
- Accepted value
- 100
- Percent error (%)
- 2
Factors affecting your result
Use consistent units for all comparable inputs. The displayed result is rounded; arithmetic is performed with the full available numeric precision. Check your source measurements before relying on the result.
Changing observed value changes the scenario being evaluated. Adjust one input at a time when comparing results, keep a copy of the assumptions, and compare values using the same unit and period. A precise arithmetic result does not make an uncertain assumption precise.
Frequently asked questions
How does the percent error calculator work?
Percent error = |observed − accepted| / |accepted| × 100.
What inputs does Percent Error Calculator need?
Enter observed value, accepted value. Choose values that correspond to the same situation and measurement convention.
How should I interpret the percent error calculator result?
Use consistent units for all comparable inputs. The displayed result is rounded; arithmetic is performed with the full available numeric precision. Check your source measurements before relying on the result.
Are my percent error calculator inputs uploaded?
No. The calculation runs in this browser. Favorites, recent tool names, theme and formatting preferences may be saved locally, but calculation inputs are not sent to a calculation server or stored by this website. Shared links do not include entered values.
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