A familiar situation
Compare an experimental measurement with a reference value to report relative measurement error.
How to use this calculator
- Enter observed value, accepted reference value.
- Select Calculate to see the answer and its breakdown.
- Keep a scenario, change an input and compare the results.
Use consistent units and check the assumptions below before applying the result.
How percent error is calculated
Signed percent error = (observed − reference)/reference × 100. Absolute percent error uses the absolute value of that signed percentage. If a measured length is 9.8 and the accepted value is 10, signed error is −2% and absolute error is 2%.
Signed error=(observed−reference)/reference×100; absolute error=|signed error|.If a measured length is 9.8 and the accepted value is 10, signed error is −2% and absolute error is 2%.
Assumptions & useful context
The result depends on the values you enter and the method described above. Displayed numbers may be rounded; calculations use the unrounded values. Check that this model matches your situation before relying on it.
Frequently asked questions
Why enter the accepted value as nonzero?
It is the denominator that defines relative error.
Does a negative signed result mean the measurement is wrong?
It indicates the observed value is below the reference; magnitude is captured by absolute error.