ARCHIVED: What is the storage capacity of my floppy diskette?

This content has been archived, and is no longer maintained by Indiana University. Resources linked from this page may no longer be available or reliable.

The storage capacity of a floppy diskette depends on whether it is a high-density or double-density diskette, and whether it is a 3 1/2" diskette or a 5 1/4" diskette. Using standard DOS formats, double-sided diskettes have the following capacities:

Type Capacity
3 1/2" double density 720KB
3 1/2" high density 1.44MB (1440KB)
3 1/2" extra high density 2.88MB (2880KB)
3 1/2" LS 120 high capacity FDD
120MB (requires LS 120 drive)
5 1/4" double density 360KB
5 1/4" high density 1.2MB (1200KB)

Keep in mind that the diskettes have to be formatted properly, at the proper density. It is possible, for instance, to format a 3 1/2" double-density diskette at high density and store 1.44MB of data on it, but this is a risky thing to do, since the media was not designed to store data at such high densities.

The best way to identify diskettes is by relying on printed markings. Double-density diskettes are usually marked "DD", "2DD", or "2S2D". High-density diskettes are marked "HD", "2HD", or "2SHD". Extra high density diskettes (which are rare and require a computer with a compatible drive, having a capacity of 2.8MB) are usually marked "ED".

Double-density 5 1/4" diskettes usually have a hub ring, while high-density diskettes generally do not (although there may be exceptions). High-density 3 1/2" diskettes have a square hole on the diskette shell in the top left corner (when the diskette is oriented face up with its shutter down). Double-density 3 1/2" diskettes lack this hole. Extra high density diskettes have holes that are located lower than the ones on high-density diskettes.

This is document adox in the Knowledge Base.
Last modified on 2018-01-18 09:12:00.

Contact us

For help or to comment, email the UITS Support Center.