Cubic inch

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A cubic inch (plural: cubic inches) is a non-SI unit of volume, equal to the volume of a cube with sides of one inch.

Cubic inches are still sometimes used as a unit of measurement (in engineering contexts, not household contexts) in the United States and Canada, although SI is continuing to gradually displace non-SI usage.

[edit] Notation conventions

The following symbols are used to denote cubic inches:

[edit] Equivalence with other units of volume

1 cubic inch (assuming an international inch) is equal to:

[edit] Uses of the cubic inch

[edit] Electrical box volume

The cubic inch was established decades ago as the conventional unit in the U.S. for measuring the volume of electrical boxes; SI has not yet replaced it for this purpose.

[edit] Engine displacement

The cubic inch was formerly used (until the 1980s) to express the nominal size (displacement) of engines (e.g. 426 HEMI) for new cars, trucks, etc. It is therefore still used for this purpose in the context of the classic-car hobby, auto racing, and so forth. The auto industry nowadays uses SI for this purpose (e.g. 6.1 L HEMI). However, the actual displacement measurements of an engine are still given by many manufacturers in cubic inches (usually along with cc; e.g. the 6.1 L HEMI's published displacement is 370.0 CID/6,059 cc).^[1][2][3][4] Some examples of common CID-to-litre conversions are given below. Note that nominal sizes are not always precisely equal to actual sizes. This principle is frequently seen in engineering, tool standardization, etc. (for ease of use) and in marketing (when a big round number sounds more impressive, is more memorable, etc.).

[edit] References

[edit] See also