Cubic centimeter (cm³)

The cubic centimetre is a unit of volume equal to one millionth of a cubic metre, written cm³ and often abbreviated cc. It is the volume of a cube one centimetre on each side, and since the litre was redefined in 1964 it is exactly one millilitre. The two names describe the same quantity, but they belong to different trades and are not interchangeable in every context.

Engines are its most visible home. Motorcycle and small-engine displacement is quoted in cubic centimetres, so a 125, a 600 and a litre bike are named by the swept volume of their cylinders. Licence categories in much of the world are drawn on the same scale, with a 125 cc limit for learners in many European countries, which turns the unit into a legal boundary rather than a mere description.

Car engines cross over to litres at about a thousand cubic centimetres, purely for readability, so a 1998 cc engine is advertised as a two-litre. American practice used cubic inches for the same purpose well into the 1980s, and the conversion is worth knowing: 1000 cubic centimetres is 61 cubic inches, so a 350 cubic inch engine is 5.7 litres.

Medicine has deliberately retreated from the abbreviation. Syringes were once marked in cc and clinicians spoke that way, but handwritten cc can be misread as a unit symbol or as a pair of zeros, and medication safety bodies now place it on lists of abbreviations that should not be used. The instruction is to write mL instead, even though the quantity is identical.

Materials science keeps the unit for density. Grams per cubic centimetre is the standard way to state how heavy a substance is for its size: water is 1.00, aluminium 2.70, steel about 7.85, lead 11.34 and gold 19.3. Those numbers are memorable precisely because the cubic centimetre is small enough that everyday solids land between one and twenty.

Modelling and manufacturing use it for part volume. Computer-aided design reports the volume of a component in cubic centimetres, which converts directly to mass once a density is chosen and to material cost in additive manufacturing. It is the natural unit for anything that fits in a hand.

One cubic centimetre equals 1 millilitre, 1000 cubic millimetres, 0.000001 cubic metres, or about 0.061 cubic inches.

Cubic centimeter conversion table