Percent error between a measured/experimental value and the true/theoretical value, with absolute error.. Percent Error Calculator is a free online tool from the ToolsRift Math Calculators collection. It runs entirely in your browser — nothing to install, no signup, and your data never leaves your device.
Enter the measured (experimental) value and the true (theoretical) value and the calculator returns the percent error and absolute error.
Percent error = |measured − true| / |true| × 100%, showing how far a measurement is from the accepted value.
Percent error is usually reported as a positive magnitude regardless of whether the measurement was over or under.
In science labs, engineering and quality control to judge how accurate an experimental result is.