How it works
Volume in cubic feet ÷ 27 = cubic yards. An 80 lb bag yields ~0.6 cu ft; a 60 lb bag ~0.45 cu ft. Always order 5–10% extra — running short mid-pour is far more expensive than a leftover bag.
Quick reference
- 4" thick slab, 10×10 ft ≈ 1.24 yd³ ≈ 56 eighty-lb bags
- Most residential slabs are 4" thick; driveways 5–6"
- Footings must extend below the frost line in cold climates