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Extent Calculations

Use the following calculations when determining the collection extent in linear feet:

Container Extent
1 SB 1 linear foot
1 MB 0.5 linear feet
½* MB 0.25 linear feet
1 TF 2 linear feet
1-5 scrapbooks 2 linear feet; continue for amounts larger than 5 scrapbooks (e.g., 23 scrapbooks = 10 linear feet, 3
1 package 1 linear foot
1 object 2 linear feet
1 newspaper 1 linear foot
1 folder 0.25 linear feet
1 envelope 0.25 linear feet
1-5 film reel(s)/can(s) 1 linear foot
1-5 magnetic tape reels 1 linear foot
OS Folder, OS print box, or poster(s) 3 linear feet

Use the following formatting when listing multiple types of extent values:

  • # linear feet (# containers or items), # items. # recordings and/or transcripts
  • # bytes (# files). Specific file types

Note

½ MBs are distinguished from MBs for extent calculation purposes ONLY. When writing extent statements, list and count ½ MBs as regular MBs.

Examples:

  1. Collection A has 5 ½ MBs. Extent statement: 1.25 linear feet, 5 MBs.
  2. Collection B has 2 MBs and 3 ½ MBs. Extent statement: 1.25 linear feet, 5 MBs.