Math
Difference
Compare two values using absolute difference, net change, percentage difference, and percentage change.
Calculators / Math / Percent error
Percent error calculator
Compare an observed value with an accepted value using absolute percent error.
On this page
Absolute error2
Percent error2%
Calculator controls
How to calculate
Compare an observed value with an accepted value using absolute percent error.
Absolute error = abs(observed-accepted); Percent error = abs(observed-accepted)/abs(accepted)*100
Worked example
Observed value: 98; Accepted magnitude/value: 100.
Absolute error: 2 ; Percent error: 2 %.
Assumptions and limits
The accepted value must be nonzero. Preserve the sign separately if direction of error matters.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Compare an observed value with an accepted value using absolute percent error. The displayed figures use the inputs and formula shown on this page.
When this tool is useful
Use the percent error to compare a scenario, check an estimate, or verify a manual calculation.
Understanding your inputs
| Input | What to enter |
|---|---|
| Observed value | Enter a number of at least -1000000000000 and no more than 1000000000000. |
| Accepted magnitude/value | Enter a number of at least 0.000001 and no more than 1000000000000. |
Frequently asked questions
What should I check before using the percent error result?
The accepted value must be nonzero. Preserve the sign separately if direction of error matters.
Is this percent error result exact?
It is exact for the stated mathematical model and entered values. Real-world results can differ when rates, timing, fees, definitions or measurement conditions differ.