Each Unit in the SQA catalogue is given a credit value. The credit value relates to the expected time it will take to deliver the Unit. In most cases Units have a notional design length of 40 hours and are worth one Unit credit. However, there are some 20 hour Units worth half a Unit credit and some 80 hour Units worth two Unit credits. At Access 1 and 2 levels almost all of the Units are worth one Unit credit.

Although one credit Units have a notional design length of 40 hours, it is important to note that at Access 1 and 2 level this length is notional and that the time it takes to deliver a Unit may vary widely depending upon the individual candidate. Some candidates will pick things up easily and will be ready for assessment quickly while others will take much longer and these candidates will require more time (possibly much more than 40 hours) before they can be assessed.

Each SQA Unit is written to a standard format, the Unit specification has three main headings: