Percent Error Calculator

How the Percent Error Calculator Works

Percent error measures how close an experimental or measured value is to the true, accepted value — a staple of physics and chemistry labs. Take the absolute difference between your measured value and the actual value, divide by the actual value, and multiply by 100. The absolute value keeps the result positive, since percent error describes size of the miss, not direction.

A small percent error means an accurate measurement. What counts as “good” depends on the experiment, but lab work often aims for a few percent or less.

percent error = |measured − actual| ÷ |actual| × 100