There are three methods for the determination of the bulk density of soils, comprising: a) linear measurement method, b) immersion in fluid method, c) fluid displacement method. The linear measurement method is suitable for the determination of the bulk density of a specimen of soil of regular shape, including specimens prepared for other tests. The specimens used are either rectangular prisms or cylinders with circular cross sections. The immersion in fluid method covers the determination of the bulk density of a specimen of natural or compacted soil by measuring its mass in air and its apparent mass when suspended in fluid. The method may be used when lumps of material of suitable size can be obtained. The fluid displacement method covers the determination of the bulk density of a specimen of soil by measuring its mass in air and the mass of fluid displaced by immersion. The method may be used when lumps of material of suitable size can be obtained. If the immersion in fluid method or fluid displacement method is used, and if the fluid is likely to penetrate into the specimen (eg water) the specimen should be coated before testing to prevent fluid penetration. The bulk density of a soil is useful in the determination of the in situ overburden stress as a function of depth. If required, the dry density of a specimen may be calculated from the bulk density and the water content, if known.