How It Works

This converter works in 4 steps.

Enter the volume fraction
Type the % v/v.
Enter the pure component density
Type ρ for the pure liquid, such as 0.7893 g/mL for ethanol at 20 °C.
Enter the solution density
Type the measured or tabulated density of the mixture.
Read the mass fraction
The converter returns % w/w and the component mass per liter.

The Formula

The formula multiplies volume fraction by the ratio of component density to solution density.

Mass fraction w = φ × ρ_component / ρ_solution

Component mass per liter g/L = φ × ρ_component × 1,000

Reverse φ = w × ρ_solution / ρ_component

w:: Mass fraction
φ:: Volume fraction
ρ_component:: Pure component density (g/mL)
ρ_solution:: Mixture density (g/mL)

Worked example

70% v/v ethanol has ρ_solution = 0.8855 g/mL. w = 0.70 × 0.7893 / 0.8855 = 0.624, so the mix is 62.4% w/w ethanol.

Conversion Table

The conversion table converts 7 ethanol-water mixtures at 20 °C from % v/v to % w/w.

Ethanol % v/v	Solution density	Ethanol % w/w	Ethanol g/L
95% v/v	0.8114 g/mL	92.4% w/w	749.8 g/L
80% v/v	0.8599 g/mL	73.4% w/w	631.4 g/L
70% v/v	0.8855 g/mL	62.4% w/w	552.5 g/L
60% v/v	0.9095 g/mL	52.1% w/w	473.6 g/L
50% v/v	0.9302 g/mL	42.4% w/w	394.7 g/L
40% v/v	0.948 g/mL	33.3% w/w	315.7 g/L
10% v/v	0.9849 g/mL	8.01% w/w	78.93 g/L

Pure ethanol density 0.7893 g/mL at 20 °C. Solution densities from standard alcoholometric tables.

What Is the Volume Fraction-to-Mass Fraction Converter?

The Volume Fraction-to-Mass Fraction Converter is a tool that converts a volume fraction (% v/v) into a mass fraction (% w/w) using the pure component density and the solution density. For ethanol-water at 20 °C (68 °F), 70% v/v equals about 62.4% w/w.

Volume fraction and mass fraction differ when the component and the solution have different densities. Ethanol (0.7893 g/mL) is lighter than water, so ethanol's mass fraction is lower than its volume fraction. The converter accepts any liquid pair and returns % w/w, g/L, and the mass of component in a chosen volume.

Common Uses

There are 5 main uses of this converter.

Spirits and beverage labeling
Distillers convert alcohol by volume (ABV) into mass percent.
Hand sanitizer formulation
Formulators match % v/v targets with mass-based batching.
Gravimetric preparation
Labs weigh components for alcohol-water mixtures.
Solvent recovery
Plants convert volume-based readings into mass balance terms.
Customs and tax reports
Producers convert between volume and mass bases for duty reports.

Volume Fraction-to-Mass Fraction Converter