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.
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Where can you learn more?
Read field notes on estimating and materials, or browse every calculator we make.
What should you read before you order materials?
Field notes from real jobs that explain the numbers behind this calculator.
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