How to Calculate Degree of Saturation

The degree of saturation is the ratio of the volume of water in a soil to the volume of voids.

Where:
S = Degree of Saturation
V_w = Volume of water (m³ or ft³)
V_v = Volume of voids (m³ or ft³)
V_g = Volume of air (m³ or ft³)

The degree of saturation is thus a ratio which can be between 0 and 1. It can also be expressed as a percent.

It is the percentage of the void space which is filled with water. The rest is air.