24×40 Concrete Slab Cost
A 24×40 slab covers 960 square feet. Here's the concrete, bags and cost for 2026 — a common size for a shop / barn.
Concrete (4", waste in)
13.04 yd³
587 × 80 lb bags
Materials (ready-mix)
$1,630 – $2,477
delivered, 4" slab
Installed by a pro
$5,280 – $11,520
4" slab, national average
24×40 slab cost calculator
Adjust thickness, waste or region — the cost updates live.
Waste & region
Order extra for spillage & uneven subgrade. 10% is typical.
Installed cost estimate
$5,280 – $11,520
960 sq ft · 13.04 yd³ concrete
Bags of concrete needed (rounded up)
587
80 lb
783
60 lb
939
50 lb
1,174
40 lb
- Ready-mix (delivered)
- $1,630 – $2,477
- Bagged mix (80 lb, DIY)
- $3,229 – $5,283
- Installed by a pro
- $5,280 – $11,520
Estimate only — not a quote. Bag counts are rounded up and include a 10% waste allowance.
24×40 slab cost by thickness
| Thickness | Concrete | 80 lb bags | Ready-mix | Installed |
|---|---|---|---|---|
| 4" | 13.04 yd³ | 587 | $1,630 – $2,477 | $5,280 – $11,520 |
| 5" | 16.3 yd³ | 734 | $2,037 – $3,096 | $6,000 – $12,240 |
| 6" | 19.56 yd³ | 880 | $2,445 – $3,716 | $6,720 – $12,960 |
Includes a 10% waste allowance; bag counts rounded up. National US averages, January 2026.
You'll also need
Sized for this exact slab — tap any item to open its calculator with your measurements already filled in.
24×40 concrete slab: what to expect
A 24×40 slab covers 960 square feet. At the standard 4" thickness it takes about 13.04 cubic yards of concrete once you allow 10% for waste, which is roughly 587 × 80 lb bags if you mix by hand. Stepping up to 6" — sensible if it'll carry a vehicle — raises that to about 19.56 cubic yards.
Budget around $5,280 – $11,520 to have a 4" slab this size poured and finished by a contractor, or roughly $1,630 – $2,477 in ready-mix if you're doing the labor yourself. On top of the concrete you'll need about 13.63 yd³ of gravel base and 67 sticks of rebar.
Compare nearby sizes
Planning something bigger or smaller? Jump straight to the cost for a nearby size.
Volumes use standard bag yields and a 10% waste allowance; costs are national US averages that vary by region, mix and finish. See our methodology for exactly how each figure is worked out, or check the reference sources: