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Concrete Calculator
Enter the dimensions of what you are pouring. This gives you the volume in cubic yards for a ready-mix order, and the bag count if the pour is small enough to mix on site.
Your numbers
Result
Order this much
5.43
cubic yards
- Exact volume
- 4.94cubic yards
- 80 lb bags0.60 cu ft each
- 245bags
- 60 lb bags0.45 cu ft each
- 326bags
- Volume
- 133.3cubic feet
- Slab area
- 400sq ft
How this is calculated
- Volume in cubic feet = length × width × (thickness in inches ÷ 12).
- Cubic yards = cubic feet ÷ 27.
- Order volume = cubic yards × (1 + allowance).
- An 80 lb bag yields about 0.60 cubic feet; a 60 lb bag about 0.45.
Before you order
- Past about half a cubic yard, bags stop making sense - that is roughly 20 eighty-pound bags for one small pad, mixed and placed before any of it starts setting.
- Ready-mix plants have a minimum order and usually charge a short-load fee under it. Ask before you book.
- Order slightly long, never slightly short. A cold joint from a half-hour wait for a second truck is a permanent defect in the slab.
- This is volume only. Rebar or mesh, vapour barrier, forms, and the compacted base underneath are separate.
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