Concrete Tools
Order the right amount — cubic yards and exact bag counts.
Slab / Footing Yardage
Rectangular pour: length × width × thickness.
Concrete needed
1.235 yd³
33.33 ft³
Or in bags
56 × 80lb
or 75 × 60lb bags
Tip: order ~10% extra for spillage, uneven subgrade, and over-excavation.
Column / Tube (Sonotube)
Round piers or footings: π r² × height.
Total concrete
0.465 yd³
12.57 ft³ for 4
Or in bags
21 × 80lb
or 28 × 60lb bags
Concrete Quick Reference
- 1 cubic yard = 27 cubic feet. That's the number everything comes back to.
- Bag yield: an 80 lb bag ≈ 0.60 ft³; a 60 lb bag ≈ 0.45 ft³.
- Slab math: ft³ = L(ft) × W(ft) × [thickness(in) ÷ 12]. Divide by 27 for yards.
- Rule of thumb: ~1 yd³ covers ~80 ft² at 4″, ~65 ft² at 5″, ~54 ft² at 6″.
- Order smart: ready-mix short loads bill a fee — round up to the next ¼ yard and add waste.
