Calculyn

Concrete Calculator

Calculate cubic yards and bags of concrete for a slab.

ft
ft
in

Results update as you type.

Concrete needed

1.23cubic yards
Cubic feet
33.3
80 lb bags
56
60 lb bags
75
Concrete needed1.23

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How it works

Multiply length × width × thickness to get volume, then convert cubic feet to cubic yards.

Formula

Yards = L × W × (D ÷ 12) ÷ 27

Example

A 10×10 ft slab, 4 in thick, needs 1.23 cubic yards.

Assumptions & limitations

  • Material estimates only — buy 5–10% extra for waste and cuts.
  • Check coverage figures on your product label.

Frequently asked questions

Should I order extra?

Yes, add 5–10% for spillage and uneven ground.