The cubic centimeter (\(\text{cm}^3\)) and the milliliter (\(\text{mL}\)) are often confused when measuring volume. While they have distinct origins—one derived from length and the other a unit of capacity—they are both fundamental components of the metric system. This article clarifies the relationship between these two units and explains why they are used interchangeably.
The Direct Equivalence of \(\text{cm}^3\) and \(\text{mL}\)
The simplest answer is that one cubic centimeter (\(\text{1 cm}^3\)) is exactly equal to one milliliter (\(\text{1 mL}\)). This precise 1:1 relationship means that any measurement expressed in one unit can be instantly converted to the other without calculation.
This equivalence is sometimes expressed using the non-standard abbreviation “cc,” which stands for cubic centimeter, especially in medical and automotive fields. Therefore, \(1 \text{ cc}\), \(1 \text{ cm}^3\), and \(1 \text{ mL}\) all represent the identical volume. This direct interchangeability simplifies volume measurements for everything from laboratory work to administering medication.
Understanding Volume: The Definitions and Metric Basis
The conceptual difference between the units lies in their derivation. A cubic centimeter (\(\text{cm}^3\)) is a unit of displacement volume derived from the metric base unit of length, the meter. It represents the volume contained within a cube measuring one centimeter on all three sides.
The milliliter (\(\text{mL}\)) is a unit of capacity based on the liter (L), the primary metric unit for liquid volume. The prefix “milli-” signifies one-thousandth, meaning \(1 \text{ mL}\) is one-thousandth of a liter (\(1 \text{ L} = 1,000 \text{ mL}\)).
The metric system connects these units through the liter. One liter was defined as the volume of a cube measuring ten centimeters on each side, which is one cubic decimeter (\(1 \text{ dm}^3\)). Since \(1 \text{ dm}^3\) contains \(1,000 \text{ cm}^3\), this establishes the relationship \(1 \text{ L} = 1,000 \text{ cm}^3\). This fundamental link ensures that one milliliter, being one-thousandth of a liter, must equal one cubic centimeter.
Practical Use and Common Conversions
The direct equivalence of \(\text{cm}^3\) and \(\text{mL}\) is highly practical across several fields. In medicine, dosages are frequently measured and administered using syringes marked in milliliters (\(\text{mL}\)), but the volume is sometimes verbally referred to as “cc”. For example, a prescription for \(5 \text{ mL}\) of a liquid medication is the same volume as \(5 \text{ cc}\).
This relationship also simplifies conversions to the larger liter unit. Since \(1 \text{ cm}^3\) equals \(1 \text{ mL}\), \(1,000 \text{ mL}\) is equivalent to \(1,000 \text{ cm}^3\), which is precisely \(1 \text{ L}\). The automotive industry also uses the \(\text{cm}^3\) unit to specify engine displacement, often written as \(\text{cc}\), such as a “1,600 cc” engine, which is a volume of \(1.6 \text{ L}\).