{{Short description|Unit of volume}} {{More citations needed|date=February 2022}} {{Use American English|date=February 2023}} {{Use mdy dates|date=February 2023}} {{Infobox unit | name = Cubic inch | image = Chevy502CID.jpg | caption = An engine with a swept piston displacement of 502 cubic inches | standard = Nonstandard | quantity = volume | symbol = in<sup>3</sup> | symbol2 = cu in | units1 = SI derived units | inunits1 = {{val|16.387064|ul=mL}} | units2 = US customary | inunits2 = {{sfrac|231}} US gallon | units3 = nonstandard | inunits3 = {{sfrac|1728}} ft<sup>3</sup> }}
The '''cubic inch''' (symbol '''in<sup>3</sup>'''), sometimes abbreviated '''cu in''', is a unit of volume in the Imperial units and United States customary units systems. It is the volume of a cube with each of its three dimensions (length, width, and height) being one inch long which is equivalent to {{sfrac|231}} of a US gallon.<ref name="IEEE 260.1-2004">{{cite tech report |title=IEEE Standard Letter Symbols for Units of Measurement (SI Customary Inch-Pound Units, and Certain Other Units) |title-link=IEEE Std 260.1-2004 |institution=IEEE |date=2004 |number=260.1-2004 }}</ref>
The cubic inch and the cubic foot are used as units of volume in the United States, although the common SI units of volume, the liter, milliliter, and cubic meter, are also used, especially in manufacturing and high technology. One cubic inch is exactly {{val|16.387064|ul=mL}}.
One cubic foot is equal to exactly {{Convert|1728|cuin|L|9}}, as 12<sup>3</sup> = 1728.
==Notation conventions== * The following abbreviations have been used to denote the cubic inch: cubic in, cu inch, cu in, cui, cu. in. * The IEEE standard symbol is: in<sup>3</sup><ref name="IEEE 260.1-2004" /> * In internal combustion engines, the following abbreviations are used to denote cubic inch displacement: c.i.d., cid, CID, c.i., ci * The National Electrical Code established the cubic inch as the conventional unit in North America for measuring the usable volume of electrical boxes. A "cu in" rating is embossed on each box.{{Citation needed|date=May 2026}}
==Equivalence with other units of volume== One cubic inch is equal to: * Exactly {{sfrac|1|1728}} cubic feet * Exactly {{sfrac|1|231}} US gallon * Exactly {{sfrac|4|231}} US liquid quart * Exactly {{sfrac|8|231}} US liquid pint * Exactly {{sfrac|32|231}} US gill * Exactly {{sfrac|128|231}} US fluid ounce * Exactly {{sfrac|1|25|231}} US tablespoons * Exactly {{sfrac|3|25|77}} US teaspoons * Exactly {{sfrac|4|100|231}} US fluid drams * Exactly {{sfrac|50|107521}} US bushel * Exactly {{sfrac|1600|107521}} US dry quart * Exactly {{sfrac|3200|107521}} US dry pint * ≈0.00360465 imperial gallons * ≈0.0144186 imperial quarts * ≈0.0288372 imperial pints * ≈0.1153488 imperial gills * ≈0.576744 imperial fluid ounces * ≈1.153488 imperial tablespoons * ≈4.613952 imperial fluid drams * ≈0.00045058 imperial bushels * Exactly {{sfrac|1|9702}} barrel of crude oil * Exactly {{convert|1.0000000|in3|mL|disp=out|abbr=off|sp=us}}
==See also== * Conversion of units * Orders of magnitude (volume) * Square inch
==References== {{Reflist}}
{{Imperial units}} {{United States Customary Units}}
Category:Customary units of measurement in the United States Category:Imperial units Category:Units of volume