Why is transformer oil density expressed in kg/m�?

Density is expressed in kg per cubic meter because it is the SI unit used in engineering calculations for volume to mass conversion, logistics, containment sizing, and thermal design. Shipping is often priced by mass, tanks are sized by volume, and spill risk is managed by volume, so density links those quantities. Using kg/m� also supports temperature correction methods, since density changes with temperature, which affects the weight of oil delivered and the calibration of level to volume calculations.