What is the difference between CC and mL?

CCs (cubic centimeters) and mL (milliliters) are both units of volume that are equal to each other, but derived from different base units. A volume in CCs can be converted to mL simply by multiplying by 1, because 1 CC is equal to 1 mL.

The centimeter is derived from the meter, and is exactly 1 percent of a meter. A cubic centimeter is exactly 0.0001 percent of a cubic meter. The mL is derived from the liter, which unlike a meter, is already a unit of volume. A mL is exactly 0.001 percent of a liter. When measuring a given volume of liquid with a ruler, it is most practical to determine the volume in CCs or cubic meters before converting it to liters or mLs.