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Percent Error Calculator

Compare an experimental (measured) value to the theoretical (actual) value.

Percent error formulas

Percent error|experimental − theoretical||theoretical| × 100

Worked examples

  1. You measure gravity as 9.6 m/s². The accepted value is 9.81 m/s².

    1. |9.6 − 9.81|9.81 × 100 = 0.219.81 × 100

    Answer: ≈ 2.14%

  2. Water boils at 98.5 °C in your experiment (theory: 100 °C).

    1. 1.5100 × 100

    Answer: 1.5%

Tips & common mistakes

  • Divide by the theoretical (true) value, not the measured one.