Concrete Slab Cost by Size
Concrete, bags and installed price for 27 common slab sizes, from an 8 × 8 hot tub pad to a 40 × 60 pole barn floor. Each size has its own page with a full materials list, bags vs. ready-mix, pour-day notes and a calculator set to that size.
Quick answer: installed concrete slabs run about $7 to $13 per sq ft at 4 inches. Small slabs cost more per foot (an 8 × 10 is about $8.50 to $15.00) because delivery and setup are spread over less area; a 40 × 60 is about $6.50 to $12.50.
Hot tub & equipment pads
| Size | Area | Thickness | Concrete (+10%) | 80-lb bags | Installed | Per sq ft |
|---|---|---|---|---|---|---|
| 8x8 slab | 64 sq ft | 4 in | 0.87 yd³ | 40 | $590–$990 | $9.00–$15.50 |
Sheds & storage buildings
| Size | Area | Thickness | Concrete (+10%) | 80-lb bags | Installed | Per sq ft |
|---|---|---|---|---|---|---|
| 8x10 slab | 80 sq ft | 4 in | 1.09 yd³ | 49 | $700–$1,190 | $8.50–$15.00 |
| 10x10 slab | 100 sq ft | 4 in | 1.36 yd³ | 62 | $840–$1,430 | $8.00–$14.50 |
| 10x12 slab | 120 sq ft | 4 in | 1.63 yd³ | 74 | $970–$1,680 | $8.00–$14.00 |
| 10x16 slab | 160 sq ft | 4 in | 2.17 yd³ | 98 | $1,240–$2,170 | $7.50–$14.00 |
| 12x16 slab | 192 sq ft | 4 in | 2.61 yd³ | 118 | $1,450–$2,560 | $7.50–$13.50 |
| 16x24 slab | 384 sq ft | 4 in | 5.21 yd³ | 235 | $2,710–$4,880 | $7.00–$13.00 |
Patios
| Size | Area | Thickness | Concrete (+10%) | 80-lb bags | Installed | Per sq ft |
|---|---|---|---|---|---|---|
| 12x12 slab | 144 sq ft | 4 in | 1.96 yd³ | 88 | $1,130–$1,970 | $7.50–$14.00 |
| 12x15 slab | 180 sq ft | 4 in | 2.44 yd³ | 110 | $1,370–$2,410 | $7.50–$13.50 |
| 12x20 slab | 240 sq ft | 4 in | 3.26 yd³ | 147 | $1,770–$3,140 | $7.00–$13.50 |
| 16x20 slab | 320 sq ft | 4 in | 4.35 yd³ | 196 | $2,290–$4,100 | $7.00–$13.00 |
| 20x20 slab | 400 sq ft | 4 in | 5.43 yd³ | 245 | $2,810–$5,060 | $7.00–$13.00 |
Carports & parking pads
| Size | Area | Thickness | Concrete (+10%) | 80-lb bags | Installed | Per sq ft |
|---|---|---|---|---|---|---|
| 10x20 slab | 200 sq ft | 4 in | 2.72 yd³ | 123 | $1,510–$2,660 | $7.50–$13.50 |
| 12x24 slab | 288 sq ft | 4 in | 3.91 yd³ | 176 | $2,090–$3,730 | $7.00–$13.00 |
Garages
| Size | Area | Thickness | Concrete (+10%) | 80-lb bags | Installed | Per sq ft |
|---|---|---|---|---|---|---|
| 20x24 slab | 480 sq ft | 5 in | 8.15 yd³ | 367 | $3,580–$6,330 | $7.00–$13.50 |
| 24x24 slab | 576 sq ft | 5 in | 9.78 yd³ | 440 | $4,250–$7,540 | $7.00–$13.50 |
| 20x30 slab | 600 sq ft | 5 in | 10.19 yd³ | 459 | $4,420–$7,850 | $7.00–$13.50 |
| 24x30 slab | 720 sq ft | 5 in | 12.22 yd³ | 550 | $5,250–$9,350 | $7.00–$13.00 |
| 24x36 slab | 864 sq ft | 5 in | 14.67 yd³ | 660 | $6,260–$11,170 | $7.00–$13.00 |
Shops, pole barns & large buildings
| Size | Area | Thickness | Concrete (+10%) | 80-lb bags | Installed | Per sq ft |
|---|---|---|---|---|---|---|
| 30x30 slab | 900 sq ft | 6 in | 18.33 yd³ | 825 | $6,960–$12,190 | $7.50–$14.00 |
| 30x40 slab | 1,200 sq ft | 6 in | 24.44 yd³ | 1,100 | $9,190–$16,140 | $7.50–$13.50 |
| 24x50 slab | 1,200 sq ft | 6 in | 24.44 yd³ | 1,100 | $9,210–$16,170 | $7.50–$13.50 |
| 30x50 slab | 1,500 sq ft | 6 in | 30.56 yd³ | 1,375 | $11,430–$20,100 | $7.50–$13.50 |
| 40x40 slab | 1,600 sq ft | 6 in | 32.59 yd³ | 1,467 | $12,160–$21,400 | $7.50–$13.50 |
| 40x60 slab | 2,400 sq ft | 6 in | 48.89 yd³ | 2,200 | $18,090–$31,920 | $7.50–$13.50 |
Driveways
| Size | Area | Thickness | Concrete (+10%) | 80-lb bags | Installed | Per sq ft |
|---|---|---|---|---|---|---|
| 12x40 slab | 480 sq ft | 5 in | 8.15 yd³ | 367 | $3,610–$6,370 | $7.50–$13.50 |
| 20x40 slab | 800 sq ft | 5 in | 13.58 yd³ | 612 | $5,820–$10,380 | $7.00–$13.00 |
Installed low end: plain broom-finish slab with ready-mix at $150/yd³ plus a $120 delivery fee, forms and labor at $3.50/sq ft. High end: the calculator's default scope (adds a vapor barrier and #4 rebar at 18 in, labor at $5.00/sq ft) plus 25% contractor overhead and profit. DIY materials: the cheaper of ready-mix or $6.50 80-lb bags, plus forms, up to vapor barrier and rebar. Site excavation and a gravel base are extra (about $1.40 to $3.30 per sq ft).
How These Prices Are Worked Out
Every size is priced with the same line items as the slab cost calculator: ready-mix concrete with a delivery fee, forms, vapor barrier, #4 rebar, a broom finish and labor, at U.S. average prices. The thickness shown is the usual one for that kind of slab (4 inches for pads, sheds and patios, 5 for garages and driveways, 6 for shops and barns); each size page also lists 4, 5 and 6 inches. Excavation, a gravel base, a thickened edge, a pump and permits are extra and are listed on each page.
For a size that isn't here, enter it in the calculator, or use the cubic yard and bags calculators.
Slab Size Questions
Delivery fees, setup and the minimum crew time are about the same for a small slab as a large one. At 4 inches, an 8 x 10 slab works out to about $8.50 to $15.00 per sq ft installed and a 40 x 60 slab to about $6.50 to $12.50.
Around 1.3 cubic yards with a rented mixer, which is a 4-inch slab of roughly 110 sq ft. Below that, bags usually cost less once the delivery and short-load fees are counted.
Each size page leads with the usual thickness for its project type: 4 inches for pads, sheds and patios, 5 inches for garages and driveways, and 6 inches for shops and barns. Every page also lists 4, 5 and 6-inch quantities.