I have developed and implemented a computer subroutine (UNCERT) that greatly simplifies the immense problems associated with most uncertainty analyses. This paper presents an overview of the most fundamental and important concepts in uncertainty analysis, a technique which can be used by a test engineer to estimate the accuracy of measured data and values calculated from measured data. Implementation of these uncertainty concepts in a computer code is also explained. Some of the results of an uncertainty analysis which was accomplished for a turbine engine compressor test are used to illustrate the analysis procedure and results. Finally, the benefits of doing an uncertainty analysis as part of a test are briefly discussed.