Percent Error Calculator
Calculate percent error and absolute difference from a measured value and an accepted value.
Use the same unit for both values. The accepted value cannot be zero because it is the denominator in the calculation.
Data handling
Storage and export controls
- Retention
- The tool's working state is kept only while this page is open. Inputs and results are not saved to persistent storage by Got A Tool.
- Export
- The tool may prepare a result after you run it. It downloads or copies it only when you choose that action.
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How it works
Percent Error Calculator: a practical guide
A percent error calculator compares a measured value with an accepted reference value. It reports the size of the difference as a percentage of the accepted value, making the formula and denominator explicit.
- STEP 01
Enter the measured or experimental value.
- STEP 02
Enter the accepted or reference value in the same unit.
- STEP 03
Calculate to review the percent error and absolute difference.
What this tool does and its limits
Percent error is the absolute value of measured value minus accepted value, divided by the absolute accepted value, multiplied by 100. The absolute-value form reports the size of the discrepancy without labeling it as too high or too low. The accepted value cannot be zero because division by zero is undefined. This tool does not select a reference value, measure uncertainty, or determine whether an error is acceptable.
Inputs, selected files, and results stay in your browser. The tool does not upload them to Got A Tool or save them to persistent storage.
Questions
Percent Error Calculator details
Why is percent error positive here?
This version uses the conventional absolute-difference formula, which measures the size of the discrepancy. It does not show whether the measured value was above or below the reference.
Can the accepted value be zero?
No. Percent error uses the accepted value as its denominator, so a zero accepted value would make the formula undefined.
Is percent error the same as percent difference?
No. Percent error compares a measured value with an accepted reference. Percent difference commonly compares two values when neither is the accepted reference.
Does a low percent error prove a measurement is accurate?
No. It is one arithmetic comparison. Measurement quality also depends on the reference, method, uncertainty, and context.
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