Measurement context matters
Percent error is useful in labs and quality checks, but it does not explain why the error happened. Instrument precision, calibration, sampling and method bias can all affect results.
Example
If the measured value is 9.8 and the accepted value is 10, the absolute error is 0.2. The percent error is 0.2 / 10 x 100 = 2%.
Common mistakes
Do not use percent error when the accepted value is zero; division by zero makes the percentage undefined. Also avoid hiding whether the measured value was above or below the accepted value if direction matters.
Limitations
Percent error summarizes size of error, not measurement uncertainty. For repeated measurements, standard deviation or confidence intervals may be more useful.
Last reviewed: 2026-05-17