Percentage error calculator
Percentage Error Calculator
Enter an observed value and the true or accepted value to calculate the absolute error and percentage error. The accepted value must not be zero.
Percentage error
2%
The observed value is 2 above the accepted value. The percentage error is 2%.
Absolute error
2
Observed position
Above accepted value
How it works
Measure error against the accepted value
Percentage error treats the accepted value as the reference. First find the absolute gap, then compare that gap with the magnitude of the accepted value.
Formula
percentage error = (|observed − accepted| ÷ |accepted|) × 100
The accepted value cannot be zero. The absolute values keep percentage error non-negative and support negative accepted values correctly.
Worked example
- 1. Start with observed value 102 and accepted value 100.
- 2. Find the absolute error: |102 − 100| = 2.
- 3. Divide 2 by |100| = 100 to get 0.02.
- 4. Multiply 0.02 by 100 to get 2% percentage error.
Choose the right comparison
- Percentage error: one value is the accepted or true reference.
- Percentage difference: neither value is the reference, so their average is used.
- Percentage change: one value is the original and the other is the later value.
Related calculators
Continue through the comparison tools
Use percentage difference when neither value is accepted, or percentage change when you are measuring movement from an original value.
No accepted baseline
Percentage Difference Calculator
Compare two values symmetrically when neither one is the accepted reference.
Change over time
Percentage Change Calculator
Measure movement from an original value to a new value.
Part-to-whole ratio
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Find what percentage one number represents of another.
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Browse the complete PercentageTools calculator directory.