How to Use Percent Error Calculator

Enter the true Value.

Enter the observed Value.

Press Calculate

Percent Error Calculator


How to calculate Percent Error

Percent Error Formula: (experimental value - accepted value)/ accepted value x 100

We measure the volume of a large bottle, we measured the volume to be 4 liters, although the real value is 3 liters. Therefore ((4 - 3)/3) x 100 = 33.33 is our percent error in this case.

Let's use one more example, we measure the volume of another gigantic bottle, we measure the volume to be 8 liters, the real value is 10 liters. Therefore ((8-10)/10) x 100 = 20 is or percent error.
Percent Error Examples
True Value Estimated Value Percent Error True Value Estimated Value Percent Error
37925333.24555101500533.245
29114948.79771093337448.797
834743.37358786458443.373
11317151.32755091284651.327
19414127.3263479492527.32
28420627.46563995421127.465


Definition: Percent Error is a method used to measure the difference between the actual number and the estimated number, expressing the error in a percentage.

Calculating a percent error tells you the size of your errors when you measured something for an experiment. The bigger the error percentage the larger the error was and it was far from the real value, while the smaller the error percentage the closer you were to the real value.

It is often used in science to compare the difference between the expected value and the experimental value. A Percent error can be negative as well as positive, if the result is negative it means the experimental value is less than the accepted value while a positive percent error means the experimental value is large than the accepted value.The absolute value is used to avoid confusion with a negative error.