Concrete Calculator
Cubic yards of ready-mix to order — or bags to buy — for slabs, footings, and post holes, with a waste allowance so you never run short mid-pour.
FAQ
- How much concrete do I need?
- Volume is length × width × thickness, converted to cubic yards (1 yard = 27 cubic feet). This tool computes it for slabs, footings, and round post holes, multiplies by quantity, and adds a waste allowance for spillage and uneven subgrade.
- Bags or ready-mix?
- Order ready-mix by the cubic yard for anything over about half a yard — bags get expensive and labor-intensive fast. Bags (40, 60, or 80 lb) make sense for small jobs like a few post holes or a small pad.
- Why round up?
- A concrete pour can't be paused to run to the store — if you come up short on a slab, the cold joint is a permanent weak point. Always order a little extra; leftover is far cheaper than a failed pour.
Rooms you can plan with this tool
Real-room inspiration that uses this tool's outputs.
basement · garage
Industrial home gym — concrete floor, steel rack, exposed brick, factory pendant
industrial, modern
basement · garage · office
Modern art studio — concrete floor, large worktable, single sculptural pendant
modern, minimalist
basement · garage
Modern home gym — rubber tile, single mirror wall, restrained equipment
modern, minimalist