The five-digit numbering system used in MasterFormat 1995 and previous versions of MasterFormat, and how it compares with the six-digit numbering system in MasterFormat 2004, is described in the following example:

MasterFormat 1995: 07500 - Membrane Roofing: The first two digits ("07") indicate the Division, Level 1 of the organizational scheme. Each of the next three digits is taken individually and represents Levels 2, 3, and 4 respectively. Typically in MasterFormat 1995, the last digit, the Level 4 number, is left unassigned, represented by a zero, to provide more flexibility for individual users.

MasterFormat 2004: 07 50 00 - Membrane Roofing: The first two digits ("07") still indicate the Division, or Level 1. The next pair of numbers, in this case "50", represents Level 2, and the third pair, "00", represents Level 3. Since in this case Level 3 is unassigned, represented in MasterFormat 2004 numbers by a double zero ("00"), it means that this is a Level 2 number. And since a pair of digits represents each Level of classification, there is room to address more than ten times as many subjects at Levels 2 and 3 than there was in the 1995 edition, providing more flexibility and room for future expansion than the five-digit system was capable of supplying. In some cases a Level 4 pair of numbers has been added to give further uniform definition of the subject matter. Unlike previous versions of MasterFormat, where any work result has been defined in MasterFormat 2004, a specific number has also been assigned to facilitate improved consistent communication about more detailed subjects. The following illustrates example Level 2-4 titles and numbers for Membrane Roofing:

07 51 00 Built-Up Bituminous Roofing (Level 2)
07 51 13 Built-Up Asphalt Roofing (Level 3)
07 51 13.13 Cold-Applied Built-Up Asphalt Roofing (Level 4)