Concrete slab calculator
PROCubic yards and bags for a concrete slab.
Short answer: cu yd = (L × W × thick/12) ÷ 27. 80 lb bag ≈ 0.6 cu ft. 10 × 10 × 4" = 33 cu ft ≈ 1.24 yd³ or 56 bags of 80 lb. Enter your measurements above and the concrete slab calculator returns the quantity, unit conversions and an estimated cost instantly, in imperial or metric — no sign-up needed.
What do you need to measure?
What is the answer?
Cubic yards
1.23
80 lb bags
56
60 lb bags
75
How does the concrete slab calculator work?
cu yd = (L × W × thick/12) ÷ 27. 80 lb bag ≈ 0.6 cu ft.
What does a worked example look like?
10 × 10 × 4" = 33 cu ft ≈ 1.24 yd³ or 56 bags of 80 lb.
What do people ask most?
›Bag or ready-mix?
Under 1 cu yd: bags. Over 1 cu yd: order ready-mix.
Which outdoor construction calculator should you use next?
Where can you learn more?
Read field notes on estimating and materials, or browse every calculator we make.