Percent Error Calculator
Calculate the percent error between an experimental value and a true value. Useful for science experiments, measurements, and quality control.
Published by:
isCalculator Editorial Team
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How to use this tool?
Follow these steps to calculate the percent error:
- Enter the Experimental Value – Type the value you measured or observed in the lab (e.g., 45.2).
- Enter the True Value – Type the accepted or theoretical value (e.g., 50). This must not be zero.
- Click "Calculate Percent Error" – The result will display as a percentage.
- Interpret the result:
- If the error is less than 10%, it shows a green success alert.
- If the error is 10% or more, it shows a yellow warning alert.
Formula used: |(Experimental − True) / True| × 100%
Note: The calculator accepts any real number (positive, negative, or decimal). The true value cannot be zero.
Previous Results
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Frequently Asked Questions
Percent error measures the accuracy of a measurement by comparing the experimental value to the true value, expressed as a percentage.
Percent error = |(Experimental - True) / True| × 100%. The absolute value ensures a positive result.
A high percent error indicates a large discrepancy between the experimental and true values, suggesting possible measurement errors or inaccuracies.
