Percent Error Calculator
Calculate the percent error between an experimental (measured) value and a theoretical (accepted) value. Percent error tells you how far off a measurement is from the true value, as a percentage.
Theoretical value
Experimental value
How to Calculate Percent Error
Subtract the theoretical value from the experimental value, take the absolute value of the result, divide by the theoretical value, and multiply by 100.
A smaller percent error means a more accurate measurement. The absolute value makes the result positive regardless of whether the measurement was high or low.
Formula
% error = |experimental − theoretical| ÷ |theoretical| × 100
Example: Percent error for a measured 9.7 vs accepted 9.8:
|9.7 − 9.8| ÷ 9.8 × 100 = 1.02%