Cassette

A cassette, or compact cassette, is a small, portable audio storage format consisting of two reels of magnetizable tape enclosed in a protective plastic shell. The 3.81 mm (0.15 in) wide tape is typically coated with ferric oxide or other magnetic formulations. Playback and recording are provided by a cassette deck; the tape can be wound to play back in either direction. The length is encoded as C-60, C-90, or C-120, indicating total playing time per side.

The format was developed by Philips and introduced in 1963 as the Compact Cassette. It gained widespread consumer adoption in the 1970s and 1980s, aided by the availability of affordable players and blank tapes. Its sealed, user-friendly design made it preferable to earlier open-reel tapes, and it found use in home stereo, car audio, and boomboxes. Audio quality depends on tape formulation (ferric oxide, chromium dioxide, or metal particle) and the type of tape and heads; high-fidelity variants offered improved signal-to-noise ratios.

In addition to audio cassettes, smaller Microcassette tapes were developed for dictation and portable recorders; they use a different form factor and generally lower audio quality. In computing history, cassette tapes were also used as a data storage medium for early home computers, using audio-encoded data with a dedicated loader program.

Today, cassettes have largely been superseded by digital formats, but remain in use for archival storage, analog revival, and hobbyist collections. Proper storage—cool, dry conditions, away from strong magnetic fields—helps preserve existing tapes, though many have degraded with age.