Containers must be opened and examined to estimate collection size. Record storage boxes or Paige boxes hold 12” of papers if materials stored are legal size, and 15” of papers if materials stored are letter size. A standard document box holds 5” of papers and a “half document” box contains 2.5” of papers. Typical file drawers are 30” deep, as are many transfile cartons.
When estimating linear footage, consider the manner in which materials are stored in containers. Boxes may be filled with packets of letters still enclosed in their original envelopes, or groups of folded lectures or sermons, or piles of diaries or daybooks. As such papers are unfolded and properly foldered, they may double or triple in size.
Oversize material found in a preliminary survey should also be included in size estimates. Linear footage for this material should be measured by the height of the oversize box, not the width.
Acid-free folders likewise take up space. A case of 500 folders adds 10” to a collection, but since most foldering adds only a small percentage to the extent of a collection, it is generally not worth considering in the estimates of linear footage. If, however, letters are individually foldered (a policy that is not recommended except in unusual circumstances), then the number of folders used should be considered in making size estimates.
Electronic files cannot be represented meaningfully by a linear footage count. Instead note the number of disks, the number of files on the disks or other storage media (if known), and the presence or absence of labels or other descriptive information. These factors will affect the amount of work necessary to provide intellectual access to these files.
The Linear Footage Calculator is helpful in estimating a collection’s extent.