Concrete Takeoff
Volume of concrete for the common pours — slab, footing, wall, column, or round pier — in cubic yards and metres, plus a bag count and a waste allowance.
Number of identical elements.
- 1.36 yd³ with a 10% waste allowance (1.23 yd³ neat).
- Ready-mix is ordered by the cubic yard — most suppliers have a minimum load (often ~1 yd³) and a short-load fee.
- Bags suit small pours: 62 × 80 lb, 82 × 60 lb, or 123 × 40 lb (yields ≈ 0.60 / 0.45 / 0.30 ft³ — vary by product; check the bag).
How the takeoff works
Every pour comes down to volume. For a box shape — slab, footing, wall, or rectangular column — that's length × width × thickness. A round pier or sonotube is a cylinder: π × (diameter ÷ 2)² × height. Multiply by the quantity for repeated footings or piers. The result is shown in cubic yards (how ready-mix is ordered in the US), cubic metres, and bag counts for small jobs.
Bag yields are approximate — an 80 lb bag makes about 0.60 ft³, a 60 lb about 0.45 ft³, and a 40 lb about 0.30 ft³ — and vary with the product and how well it's consolidated, so check the bag. Add a waste allowance (5–10% is typical) for spillage and over-excavation, and remember suppliers price ready-mix by the yard with a minimum load. Estimating the area first? The drywall & paint takeoff and tributary area tools use the same dual-unit approach.
Frequently asked questions
How much concrete do I need for a slab?
Multiply length × width × thickness to get cubic feet, then divide by 27 for cubic yards. A 10 × 10 ft slab at 4 inches is about 33 cubic feet — roughly 1.23 cubic yards (1.36 with a 10% waste allowance). This tool does it in cubic yards, cubic metres, and bags.
How many bags of concrete are in a cubic yard?
About 45 × 80 lb bags, 60 × 60 lb bags, or 90 × 40 lb bags, since a cubic yard is 27 cubic feet and the bags yield roughly 0.60, 0.45, and 0.30 cubic feet each. Yields vary by product — check the bag. Bags suit small pours; larger pours are cheaper as ready-mix by the yard.
How much waste should I add to a concrete order?
A 5–10% allowance is common for spillage, over-excavation, and uneven sub-base. This tool defaults to 10% and shows both the neat and the with-waste volume. Round up to your supplier's increment and mind minimum-load fees.
How do I estimate concrete for round piers or sonotubes?
A round pier is a cylinder: volume = π × (diameter ÷ 2)² × height, times the number of piers. A 12-inch tube 4 feet deep is about 3.1 cubic feet each. Pick the "round pier / sonotube" shape and enter the diameter, height, and quantity.