Abstract: The article analyzes the definition and calculation methods of random error and measurement uncertainty,and determines that there is a similarity in nature between the two,while there are also differences between them.Random error is calculated from the standard deviation of the results of multiple repeated measurements,and uncertainty not only includes the results obtained by statistical methods,but also other factors that may have a random impact on the calibration results.By comparing and analyzing,it can effectively promote the reader’s understanding of uncertainty.Then,taking the uncertainty evaluation of precision pressure gauge as an example,the application of typical uncertainty evaluation report to quickly carry out the uncertainty evaluation of actual calibration data is discussed,and the suggestions for giving the actual uncertainty when reporting the calibration results are put forward.

Key words: Random error, Uncertainty of measurement, Uncertainty budget, Calibration