ISO 11508:2017 specifies two methods for the determination of particle density of soils calculated from the mass and the volume of soil particles. The first method (4.1) is applicable to fine soil (<2 mm diameter) and the second method (4.2) is applicable to both porous and nonporous gravel and stones (>2 mm diameter). The particle density can be used for the calculation of the proportion of solids and of the porosity of soil layers in combination with the procedure given in ISO 11272.