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Calculation Machine

Percent Error Calculator

Experimental accuracy against a true value.

Reviewed by the Calculation Machine team · How we check our maths

Your values

ⓘ Live results

Results
Percent error
0.9174%
Absolute error
0.09
Relative error
0.009174
Direction
Underestimate
Accuracy
99.0826%

Working

  1. 1% error = |9.72 − 9.81| ÷ |9.81| × 100 = 0.9174%

Quick answer

Percent error is the absolute difference between measured and true value, divided by the true value, times 100.

The formula

% error = |measured − true| ÷ |true| × 100

Worked example

Worked example

Using the values the calculator loads with.

Inputs

  • Measured value9.72
  • Accepted (true) value9.81

Result

  • Percent error0.9174%
  • Absolute error0.09
  • Relative error0.009174
  • DirectionUnderestimate
  • Accuracy99.0826%

How to use the Percent Error Calculator

  1. 1Enter your measured or experimental value.
  2. 2Enter the accepted or theoretical value.
  3. 3Read the percent error and accuracy.

Frequently asked questions

What is an acceptable percent error?

In school labs under 5% is usually good; precision physics work targets far below 1%.

Can percent error be negative?

By convention it uses absolute value, but the direction row above tells you whether you were high or low.

About this calculator