Percentage Error Calculator
Calculate percentage error.
Runs locally in your browser
Your inputs are processed locally in your browser and are not uploaded or stored by us.
Calculate the percentage error between an estimated or measured value and the actual, exact reference value.
How to calculate percentage error
- Enter the measured (or estimated) value.
- Enter the actual (or reference) value.
- Click "Calculate" to compute the absolute error and the percentage error.
Percentage Error Formula
absolute error = |measured − actual|
percentage error = (|measured − actual| / |actual|) × 100
Absolute error finds the exact difference without regard to sign. Percentage error then divides that absolute error by the absolute magnitude of the actual value, |actual|, so that the resulting percentage is always positive and proportional to the true reference magnitude.
Calculating error for a measurement
Measured value98
Actual value100
Absolute error = |98 − 100| = 2
Percentage error = (2 / 100) × 100
Result: 2%
Notes
- Negative values are fully supported. For example, measured = -98 and actual = -100 produces 2% error.
- Percentage error is undefined in this calculator when the actual/reference value is zero because the formula would divide by zero.
- Percentage error compares a measured or estimated value with a reference/actual value. Percentage change compares how a value changes from an earlier value to a later value.
- Calculations use JavaScript floating-point numbers, so some decimal results may be approximate.
- Your calculator inputs are processed locally in your browser and are not uploaded or stored by us.