Free Milk Weight to Volume calculator with clear step-by-step results.
Milk is slightly denser than water because dissolved lactose and protein outweigh the buoyancy of the fat, and the density rises as fat is removed - skimmed milk is denser than whole. Cream, being mostly fat, is the only one lighter than water.
Volume
Millilitres = grams / density for the milk type
US cups
Cups = millilitres / 236.588
For most cooking, yes - the error is under 4%. It matters for bread formulas, cheesemaking and anything where a baker's percentage is being calculated precisely.
Fat is less dense than water. Removing it leaves a higher proportion of denser solids, so the remaining liquid weighs slightly more per millilitre.