If the experimental value is less than the accepted value, the error is negative. ... If the experimental value is larger than the accepted value, the error is positive. Often, error is reported as the absolute value of the difference in order to avoid the confusion of a negative error.

Is it possible to have a negative percentage error?

Answer: If the experimental value is less than the accepted value, then the percent error is negative. Generally, the error is calculated as the measure of the absolute difference to avoid the confusion of a negative error.

What happens if you have a negative percent error?

If you are calculating percent error, the difference between the experimental value and the accepted value is an absolute value. So even if you get a negative number in your calculation, because it is an absolute value, it is positive.