How this calculator works
A cubic centimetre is exactly one millilitre. A milligram is one thousandth of a gram, or one millionth of a kilogram. Converting between them is a density calculation, not a fixed unit factor: volume equals mass divided by density. Water has a nominal density of about 1000 kilograms per cubic metre, which is 1 gram per cubic centimetre, so one milligram of water fills 0.001 cubic centimetres. A denser material packs more mass into the same space and gives a smaller volume for the same number of milligrams. The water table shows the result at that nominal density; choose a custom density for any other material.
Formula
Volume (mL or cc) = mass (mg) / density (kg/m3). Mass (mg) = volume (mL or cc) x density (kg/m3). The numeric factor is one because 1 mg is 1e-6 kg and 1 mL is 1e-6 m3, so the powers of ten cancel.
Worked example
At the nominal water density of 1000 kg/m3, 500 mg is 500 / 1000 = 0.5 mL, which is 0.5 cc. In reverse, 2 cc of water has a mass of 2 x 1000 = 2000 mg, or 2 g. For a material with a density of 2000 kg/m3, the same 500 mg would occupy only 0.25 cc.
Frequently asked questions
Is one cc always one milligram?
No. One cc of water is about 1000 mg. One cc of a denser material is heavier, and one cc of a lighter material is lighter. Only a density calculation can connect milligram and cc values.
Is cc the same as mL?
Yes. A cubic centimetre and a millilitre are the same volume, so the numbers are interchangeable. This page labels the volume column as mL = cc for that reason.
Can I use this to work out a medicine dose?
No. A dose depends on the concentration of the active ingredient, not on the density of the liquid. Follow the label or a prescriber, and never infer a dose from a mass-to-volume conversion.
Which density should I enter for a mixture?
Use a measured density for the mixture at the relevant temperature. A value for one pure ingredient can be far from the density of a solution or suspension made from several ingredients.