Concrete for a 8x12 Slab
Order 1.30 yd with 10% waste — or 54 × 80 lb bags / 72 × 60 lb bags.
By thickness
| Thickness | Cubic yards | +10% waste | 80 lb bags | Typical use |
|---|---|---|---|---|
| 4" | 1.19 | 1.30 | 54 | Patio, shed pad, walkway |
| 5" | 1.48 | 1.63 | 67 | Light vehicle traffic |
| 6" | 1.78 | 1.96 | 80 | Driveway, garage |
Bags or the truck?
For this 96 sq ft slab at 4": bags ≈ $351 (54 × 80 lb — that's 4,320 lb of mixing) vs ready-mix ≈ $259 delivered. The truck wins here. Prices are national ballparks — your local quote rules.
Adjust the numbers
Common questions
How much concrete do I need for a 8x12 slab?
A 8x12 slab at the standard 4-inch thickness needs 1.19 cubic yards of concrete — order 1.30 yards with a 10% waste margin. At 6 inches it needs 1.78 yards.
How many bags of concrete for a 8x12 slab?
At 4 inches thick: 54 bags of 80 lb concrete mix or 72 bags of 60 lb. At this volume, delivered ready-mix is usually cheaper and far less work than mixing bags.
Should I use bags or ready-mix for a 8x12 slab?
Ready-mix. Bags for this slab would cost about $351 in material and require mixing 4,320 lb by hand; a delivered order runs roughly $259 and arrives ready to pour.