Percent Error

Percent error is a measurement of the accuracy of the measurement. It is calculated using the following formula:

Note:    Percent error is often reported as a positive number- regardless of whether the experimental value is too high or low.  Frequently the absolute value of the difference between the experimental and accepted values is used, so the final percent error would be reported as a positive value.

Percent Error Practice:  Solve the following percent error problems.

1.  Sid Sloppy was not careful in his measurements. He measured the volume of a 12 oz. bottle to be 14 oz.

2.  Gilbert Goofoff was told use the balance to find the mass of a 500 g piece of metal. He goofed off for most of the lab period and then tried to finish his experiment quickly at the end. Since he was in such a rush he reported the weight of the metal as 458 g.

3.  Franny Failure was told to measure a length of copper wire 50 cm long to use for her experiment. She mistakenly measured 45 cm of wire instead, which lead to poor results in her experiment.

Check your answers to the percent error practice problems here