Sand and Cement Mix Calculator

About this calculator

Mixing mortar requires accounting for the fact that dry, loose sand and cement particles settle and compact once wetted, so the wet, in-place mortar volume is smaller than the sum of the dry ingredients poured in — this calculator applies a standard 1.33 dry volume factor to your target wet mortar volume, then splits that dry volume according to your chosen cement:sand ratio (such as 1:4 or 1:6) to find the cement volume, converts it to the number of 50 kg bags (roughly 0.0347 m³ per bag), and gives the corresponding sand volume.

Masons, DIY builders mixing mortar for brickwork or rendering, and site estimators use this to avoid the two common failure modes of eyeballing a mix: running short mid-batch, which risks an inconsistent mix if more dry material is added later, or over-ordering cement, which is one of the most expensive components by volume. Getting the ratio right also directly affects the cured mortar's strength and workability.