The S.I. unit of mass is kilogram (symbol kg) and of volume is cubic metre (symbol m3). Therefore S.I. unit of density is kg/m3 or kg m-3. The C.G.S. unit of mass is gram (symbol g) and of volume is cubic centimetre (symbol cm3). Therefore the C.G.S. unit of density is g/cm3 or g cm-3.
Relationship between kg m-3 and g cm-3