Percentage Error Calculator
Find the percentage error between an experimental (measured) value and a true (accepted) value. Used in science labs, engineering, and quality control.
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Percentage error
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Absolute error
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Relative error
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Frequently asked questions
What is the percentage error formula? ›
Percentage Error = (|Experimental − True| ÷ |True|) × 100. Example: experimental = 9.8, true = 9.81 → |9.8 − 9.81| ÷ |9.81| × 100 = 0.01 ÷ 9.81 × 100 ≈ 0.102%.
What is a good percentage error? ›
It depends on the field. In chemistry labs, under 5% is generally considered acceptable. In physics experiments, under 1–2% is good. In engineering, tolerances can be as tight as 0.1% or less. The acceptable range depends on the precision of your instruments and the requirements of your experiment.
What is the difference between percentage error and percentage difference? ›
Percentage error compares an experimental result to a known true value — the true value is in the denominator. Percentage difference compares two values of equal standing using their average as the denominator. Use percentage error when you have a known correct answer to compare against.
About this calculator
Percentage error measures how far an experimental measurement is from the accepted true value, expressed as a percentage. It is one of the most common error analysis tools in science and engineering. A lower percentage error indicates a more accurate measurement.