Calibration standards are an often neglected but very necessary piece of the puzzle for the gas industry. This paper gives insight into the issues of preparing and verifying the calibration standards used in labs every day. So that everyone is on the same page, it is important to answer a few simple questions about calibration standards. First, what is a calibration standard? A simple answer to this question is, a calibration standard is a mixture or blend of known concentrations of specified components used to confirm or determine the concentrations of these same components in a sample