Estimate how many bags of concrete you need for slabs, pads, and small pours. Enter dimensions and choose bag size.
First calculate the total concrete volume in cubic feet:
Formula: length × width × thickness (in feet)
Then divide by the yield of your chosen bag size.
Example: 10 ft × 10 ft × 4 in slab ≈ 33.33 cubic feet.
| Bag Size | Approx. Yield |
|---|---|
| 50 lb | 0.375 cu ft |
| 60 lb | 0.45 cu ft |
| 80 lb | 0.60 cu ft |
Buy 5% to 10% extra concrete for waste, spillage, form irregularities, and small miscalculations.
Use this concrete bag calculator for sidewalks, shed pads, post bases, fence footings, small patios, slab repairs, and home improvement projects.
A 10x10 slab at 4 inches thick needs about 56 bags of 80 lb concrete, depending on exact yield and waste.
Many residential slabs are 4 inches thick, though some projects require thicker pours.
Yes. For square or rectangular footings, enter the dimensions and thickness.
Yes. Always round up and buy extra to avoid running short mid-pour.