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Percent Error Calculator

Percent error between actual and expected.

Result

Percent error

5.26%

Common questions

How do I calculate percent error?

Percent Error = |Experimental Value − Theoretical Value| ÷ |Theoretical Value| × 100. For example, measured 9.8 vs. expected 10.0: |9.8−10.0|/10.0 × 100 = 2%.

What is an acceptable percent error?

It depends on the field. In chemistry labs, under 5% is generally acceptable. In physics, under 1–2% may be expected. Engineering tolerances vary by application.