Cement Calculator

Our Concrete Calculator estimates bags of pre-mixed concrete (like standard 40/60/80 lb bags) by their weight yield, the simplest approach when buying pre-mixed bags. This calculator instead works from a raw mix ratio, cement to sand to aggregate, like the common 1:2:4 general-purpose ratio, the approach used when mixing concrete or mortar from separate raw materials rather than a single pre-mixed bag.

Loose dry materials (cement, sand, aggregate) take up more space than they do once mixed with water and compacted, because dry particles have air gaps between them that close up during mixing. This calculator applies a standard bulking factor of 1.54 to convert your target finished (wet) volume into the total dry material volume you need to start with, then splits that dry volume across your mix ratio.