Percentage error is a measurement of the discrepancy between an observed (measured) and a true (expected, accepted, known, etc.) value. It is used to compare measured values to known values and assess the validity of measurements.
The calculation of percentage error involves the following steps:
For example, if the observed value is 56.891 and the true value is 62.327, the percentage error is 8.722%.
Percentage error is typically positive, but it can be negative if the observed value is smaller than the true value. Negative percentage error simply indicates that the measured value is smaller than expected.