# Specific Gravity of Soil

Written by Jerry Ratzlaff on . Posted in Geotechnical Engineering

Specific gravity of soil, abbreviated as $$SG_s$$, a dimensionless number, the mass of solids in the soil compared to the mass of water at the same volume.

## Specific Gravity of soil formulas

 $$\large{ SG_s = \frac{ \rho_s }{ \rho_w } }$$ $$\large{ SG_s = \frac{ M_s }{ V_s \; \rho_w } }$$ $$\large{ SG_s = \frac{ W_s }{ V_s } \; \gamma_w }$$

### Where:

$$\large{ SG_s }$$ = specific gravity of soil

$$\large{ \rho_s }$$  (Greek symbol rho) = density of soil

$$\large{ \rho_w }$$  (Greek symbol rho) = density of water

$$\large{ M_s }$$  = mass of soil

$$\large{ \gamma_w }$$  (Greek symbol gamma) = unit weight of water

$$\large{ V_s }$$ = volume of solid soil

$$\large{ W_s }$$ = weight of soil