Percent error calculator
Compare a measurement with an accepted value and see the size and direction of its error.
Percent error divides the absolute difference by the absolute reference value, then multiplies by 100. A zero reference is undefined and is rejected. Negative references are supported. Both inputs are limited to magnitude 1 trillion; use Percentage difference to compare two values without a reference. Change the input or settings to update your result. Results update as you type. Up to 1,000,000 characters.
Your result
How to use Percent error calculator
- Enter the measured value and the accepted reference in the same units. The main percent error is nonnegative. The signed result shows whether the measurement is higher or lower than the reference.
- A measurement of 9.5 against an accepted value of 10 has an absolute error of 0.5 and a percent error of 5%. Its signed percent error is -5%.
Useful next steps
Compare measured and accepted values
Enter the measured value and the accepted reference in the same units. The main percent error is nonnegative. The signed result shows whether the measurement is higher or lower than the reference.
Try a small example
A measurement of 9.5 against an accepted value of 10 has an absolute error of 0.5 and a percent error of 5%. Its signed percent error is -5%.
What to know
Percent error divides the absolute difference by the absolute reference value, then multiplies by 100. A zero reference is undefined and is rejected. Negative references are supported. Both inputs are limited to magnitude 1 trillion; use Percentage difference to compare two values without a reference.