Propylene Glycol Density Calculator with Mixture Percentages

Density (ρ) is mass per unit volume, measured in kg / m³ [SI] or lb / ft³ [Imperial]. Propylene glycol is denser than water, so adding glycol to a system increases the fluid density. Density decreases as temperature rises, following the relation:

ρ = m / V

Specific gravity (SG) — the ratio of fluid density to the density of water at a reference temperature — is commonly measured in the field with a hydrometer or refractometer to verify glycol concentration.

Density directly affects pump head calculations, pipe pressure drop, and mass flow rate. A fluid head calculator using water density will underestimate the head produced by a denser glycol solution. Density also drives buoyancy in stratified tanks and influences the calibration of flow meters that are not mass-based. When converting between volumetric flow (GPM) and mass flow (PPH or lb/hr), the actual density at operating temperature must be used.