Concrete Mix Ratio Calculator
Break a volume of concrete down into cement, sand, and gravel by a chosen mix ratio.
A concrete mix ratio like 1:2:3 (cement:sand:gravel) describes proportions by volume, not a fixed amount — to turn it into real quantities, add the parts together to get the total number of "shares," then split your total volume across cement, sand, and gravel in that same proportion. A general-purpose 1:2:3 mix is common for slabs and footings, while richer mixes (more cement) are used where higher strength is needed, and leaner mixes stretch material further for non-structural fill.
Frequently Asked Questions
What does a 1:2:3 concrete mix ratio mean?
It means for every 1 part cement, you use 2 parts sand and 3 parts gravel by volume — a general-purpose ratio suitable for most slabs, footings, and foundations.
How many bags of cement does a cubic yard of 1:2:3 mix need?
A cubic yard (27 cu ft) split at a 1:2:3 ratio needs about 4.5 cu ft of cement, which is roughly 4-5 standard 94 lb bags, since one bag is approximately 1 cu ft.