Percent Error Calculator
Compare a measurement with a reference or calculate symmetric percentage difference between two values.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Subtract the reference from the measured value. Take the absolute difference for the magnitude. Choose the reference magnitude or mean absolute magnitude as denominator. Divide the difference by that denominator and multiply by one hundred.
Error%=100|a−b|/|b|; difference%=200|a−b|/(|a|+|b|)
Worked example
Measured 98 against reference 100 gives 2% error and a signed difference of −2.
Assumptions and input details
Both inputs must represent the same quantity and unit. Symmetric difference uses absolute magnitudes and has no preferred reference. A zero denominator is undefined. This does not establish measurement validity.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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