How Much Concrete for a 40x60 Slab?
A 40×60 ft slab covers 2400 sq ft. At the standard 4-inch thickness it needs 29.63 cubic yards of concrete – about 1467 bags of 80 lb mix including 10% extra. Adjust the thickness below for your project.
Concrete for a 40x60 slab by thickness
| Thickness | Cubic yards | Yards +10% | 80 lb bags | 60 lb bags | Ready-mix cost* |
|---|---|---|---|---|---|
| 4 in | 29.63 | 32.59 | 1467 | 1956 | $5,378 |
| 5 in | 37.04 | 40.74 | 1834 | 2445 | $6,722 |
| 6 in | 44.44 | 48.89 | 2200 | 2934 | $8,067 |
*At about $165 per cubic yard before delivery and short-load fees. Bag counts include 10% extra.
How it is calculated
40 ft × 60 ft × (4 in ÷ 12) = 800 cu ft
800 cu ft ÷ 27 = 29.63 cubic yards
80 lb bags = 800 × 1.10 ÷ 0.60 = 1467
Which thickness do you need?
- 4 inches – patios, walkways, shed floors and most residential garage floors.
- 5–6 inches – driveways, hot tub pads, and garages for heavier trucks or RVs.
- Add 4–6 inches of compacted gravel base underneath and use rebar or wire mesh for slabs larger than about 10×10 ft.
Frequently asked questions
How many yards of concrete for a 40x60 slab?
A 40x60 slab (2400 sq ft) needs 29.63 cubic yards at 4 inches thick, 37.04 yd³ at 5 inches and 44.44 yd³ at 6 inches, before waste.
How many bags of concrete for a 40x60 slab?
At 4 inches thick with 10% extra, you need about 1467 bags of 80 lb concrete mix or 1956 bags of 60 lb mix.
Should I use bags or ready-mix for a 40x60 slab?
At 32.6 cubic yards, ready-mix delivery is usually faster and more consistent than mixing 1467 bags by hand. Many suppliers charge a short-load fee under 3–4 yards.