What This Calculator Measures
Percentage error measures how far a measured value is from a designated accepted, expected, or theoretical reference value, relative to the magnitude of that reference.
The result is non-negative. A separate signed-error metric and the interpretation show whether the measured value is above, below, or equal to the reference.
Percentage Error Formula
Formula
|Measured value − Reference value| ÷ |Reference value| × 100
The absolute reference value is the denominator, so signed measured and reference values are supported.
The reference must be nonzero. The calculator uses the reference you designate and does not determine whether it is trustworthy.
How to Calculate It
Step-by-step method
- Subtract the reference value from the measured value to find signed error.
- Take the absolute value of that error.
- Divide by the absolute reference value and multiply by 100.