How Many Bags of Concrete for a 24×24 Slab?
A 24×24 foot slab — 576 square feet — at the standard 4-inch thickness needs 7.82 cubic yards of concrete: 352 bags of 80 lb or 470 bags of 60 lb, including 10% waste.
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Answer at a glance — 24×24 ft slab (576 sq ft)
| Thickness | Cu yards | 80 lb bags | 60 lb bags | 40 lb bags |
|---|---|---|---|---|
| 3.5" | 6.84 cu yd | 308 | 411 | 616 |
| 4" | 7.82 cu yd | 352 | 470 | 704 |
| 5" | 9.78 cu yd | 441 | 587 | 881 |
| 6" | 11.73 cu yd | 528 | 704 | 1056 |
All counts include 10% waste, rounded up.
How we calculated it
- Area = 24 × 24 = 576 sq ft
- Volume = 576 × 4 ÷ 12 = 192 cu ft
- Cubic yards = 192 ÷ 27 = 7.11 cu yd
- With 10% waste = 7.82 cu yd
- 80 lb bags (45 per cu yd) → 352 bags
Bags vs. ready-mix
At 7.82 cubic yards, ready-mix delivery is almost always cheaper and faster than bags. Budget for a pump truck if the pour site isn't truck-accessible.
Thickness reference
| Use | Recommended thickness |
|---|---|
| Sidewalk, path | 4 inches |
| Patio, shed base | 4 inches |
| Driveway (cars) | 5 inches |
| Driveway (trucks/RVs) | 6 inches |
| Garage floor | 4–6 inches + rebar |
Use the Concrete Calculator to enter your exact dimensions and get a precise bag count and cost estimate.
Frequently Asked Questions
How many bags of concrete for a 24x24 slab?
A 24×24 ft slab (576 sq ft) at 4 inches thick needs 352 bags of 80 lb concrete or 470 bags of 60 lb. Includes a 10% waste factor.
How many cubic yards of concrete for a 24x24 slab?
At 4 inches thick: 7.82 cubic yards (with 10% waste). At 6 inches: 11.73 cu yd.
Should I use ready-mix or bags for a 24x24 slab?
At 7.82 cubic yards, get a ready-mix quote. Most suppliers have a minimum order — compare the per-yard price vs. bag costs before deciding.
How thick should a 24x24 concrete slab be?
For a patio or shed base: 4 inches. For a driveway with passenger cars: 5 inches. For heavy vehicles: 6 inches. Garages typically use 4–6 inches with wire mesh or rebar.
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