Formula used
Cubic yards = [length × width × (thickness ÷ 12) ÷ 27] × (1 + waste ÷ 100)
Worked cement and concrete mix example
Cement and Concrete Mix Calculator example: 18.4 ft × 9.2 ft × 4 in ÷ 12 ÷ 27 × 1.1 = 2.3 yd³. The same volume is about 105 80-lb premixed-concrete bags or 138 60-lb bags using the calculator's bag-yield constants.
From calculated volume to an order
Use cubic yards for ready-mix or whole bags for a labeled premixed concrete product; do not convert these bag counts into cement-only bags.
Where a concrete takeoff can drift
Mix design, bag yield, aggregate proportions, water content, subgrade variation, and placement loss determine how much cementitious product is actually required.
Questions specific to this calculation
Which finished dimensions define the cement and concrete mix placement?
Enter the dimensions of the concrete placement. Despite the short page name, the outputs describe ready-mix volume and premixed concrete bags—not sacks of cement powder in a site-batched mix.