Percent Error Calculator
Enter your experimental (measured) value and the theoretical (accepted) value to get the percent error. Switch modes to find the percent difference between two values with no fixed reference.
How to calculate percent error
- Enter your experimental (measured) value.
- Enter the theoretical (accepted) value you are comparing against.
- Read the percent error, computed as the absolute difference over the accepted value, times 100.
Examples
Measuring gravity
Experimental 9.8, theoretical 9.81
Percent error about 0.10%
Frequently asked questions
What is the percent error formula?
Percent error equals the absolute value of (experimental minus theoretical), divided by the absolute value of the theoretical, multiplied by 100.
What is the difference from percent difference?
Percent error compares a measurement to a known accepted value. Percent difference compares two values when neither is treated as correct.
Why must the theoretical value not be zero?
The formula divides by the theoretical value. Dividing by zero is undefined, so a zero accepted value has no percent error.
Can percent error be over 100 percent?
Yes. If your measurement is far from the accepted value, the error can exceed 100 percent. It is always reported as a positive number.
Is my data private?
Yes. All calculations run in your browser and nothing is uploaded or stored.
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