Every measurement will have a certain amount of error that naturally occurs. Whether due to the measurement system, or the person conducting the measurement, it is understandable that a miniscule amount of measurement error should be expected. Due to this, there is the maximum error. The maximum error is the amount of deviation in a measurement that is allowed. Often maximum error will be displayed as +/-, signifying the value of acceptable error above and below the exact measurement. For example, if you are measuring a pipe that is 2.0” in interior diameter, the maximum error might be 0.001”. This means that when measuring this part, if the measurement equaled 1.999” or 2.001” than these would be allowable values. Defining the maximum error is very important in order to account for expected error, but also to set a numeric value of how much of that error is acceptable to remain accurate.