About

In professional baking and dairy processing, ingredients are often measured by weight for hygiene and precision, yet recipes or packaging may require volume. Milk is denser than water, meaning 1 kg of milk does not equal 1 liter. The density of milk varies primarily based on two factors: fat content and temperature.

Fat is less dense than water, so cream is actually lighter per unit of volume than skim milk. Conversely, as temperature rises, milk expands, lowering its density. This tool uses specific gravity coefficients to provide an accurate conversion for various dairy products ranging from Skim Milk to Heavy Cream, adjusting for thermal expansion up to pasteurization temperatures.

Formulas

The volume V is derived from mass m and temperature-dependent density ρ(T).

V = mρ_base − k⋅(T − 20)

Where ρ_base is the density at 20°C, k is the thermal expansion coefficient (approx 0.0006 kg/L/°C for milk), and T is the input temperature in Celsius.

Reference Data

Dairy Product	Fat Content	Density at 4°C (kg/L)	Density at 20°C (kg/L)
Skim Milk	0.1%	1.036	1.035
Semi-Skimmed	1.5%	1.034	1.033
Whole Milk	3.5%	1.032	1.030
Light Cream	18%	1.015	1.012
Heavy Cream	36%	0.998	0.994
Water (Ref)	0%	1.000	0.998

Frequently Asked Questions

Cream contains a high percentage of butterfat. Fat is hydrophobic and less dense than water (approx 0.9 g/mL). Skim milk contains dissolved solids (lactose, proteins) which are heavier than water, increasing its overall density.

Significant enough for commercial bottling. Between 4°C (fridge temp) and 20°C (room temp), density drops by roughly 0.2%. While small for a cup, in a 10,000-liter tanker, this represents a discrepancy of roughly 20 liters.

No. Plant-based milks have different compositions of solids and fats. This calculator uses specific gravity values derived from bovine milk components.

The tool assumes a standard average of 1.030 kg/L at 20°C for 3.5% fat milk, which aligns with USDA and dairy industry standards.