How much does a 10×10 concrete slab cost?
A 10×10 slab (100 sq ft) costs $600–$1,200 at 4" thick. It is the smallest size most contractors will quote, and you will likely pay near the high end of the per-square-foot range due to minimum job charges.
Price charts by footprint
Concrete Slab Cost by Size: 10x10 to 40x40
Concrete slab cost scales with square footage — but not linearly. Smaller slabs cost more per square foot because fixed costs get spread across fewer square feet.
Below, we break down costs for every common size from 10×10 (100 sq ft) to 40×40 (1,600 sq ft), at three thickness levels. For a complete breakdown of per-square-foot pricing across the US, see our concrete slab cost per square foot guide.
Concrete Slab Cost by Size — Full Price Table
All common sizes × three thicknesses (material + labor + site prep)
| Size | Area | 4" Basic | 5" Driveway | 6" Garage |
|---|---|---|---|---|
| 8×8 | 64 sq ft | $384–$768 | — | — |
| 10×10 | 100 sq ft | $600–$1,200 | $700–$1,300 | $800–$1,500 |
| 10×12 | 120 sq ft | $720–$1,440 | $840–$1,560 | $960–$1,800 |
| 12×12 | 144 sq ft | $864–$1,728 | $1,008–$1,872 | $1,152–$2,160 |
| 12×16 | 192 sq ft | $1,152–$2,304 | $1,344–$2,496 | $1,536–$2,880 |
| 16×16 | 256 sq ft | $1,536–$3,072 | $1,792–$3,328 | $2,048–$3,840 |
| 16×20 | 320 sq ft | $1,920–$3,840 | $2,240–$4,160 | $2,560–$4,800 |
| 20×20 | 400 sq ft | $2,400–$4,800 | $2,800–$5,200 | $3,200–$6,000 |
| 20×24 | 480 sq ft | $2,880–$5,760 | $3,360–$6,240 | $3,840–$7,200 |
| 20×30 | 600 sq ft | $3,600–$7,200 | $4,200–$7,800 | $4,800–$9,000 |
| 24×24 | 576 sq ft | $3,456–$6,912 | $4,032–$7,488 | $4,608–$8,640 |
| 24×30 | 720 sq ft | $4,320–$8,640 | $5,040–$9,360 | $5,760–$10,800 |
| 30×30 | 900 sq ft | $5,400–$10,800 | $6,300–$11,700 | $7,200–$13,500 |
| 30×40 | 1,200 sq ft | $7,200–$14,400 | $8,400–$15,600 | $9,600–$18,000 |
| 30×50 | 1,500 sq ft | $9,000–$18,000 | $10,500–$19,500 | $12,000–$22,500 |
| 40×40 | 1,600 sq ft | $9,600–$19,200 | $11,200–$20,800 | $12,800–$24,000 |
| 40×50 | 2,000 sq ft | $12,000–$24,000 | $14,000–$26,000 | $16,000–$30,000 |
| 40×60 | 2,400 sq ft | $14,400–$28,800 | $16,800–$31,200 | $19,200–$36,000 |
Notice the pattern: a 10×10 slab costs $6–$12/sq ft, while a 40×40 slab costs the same $6–$12/sq ft. The price per square foot does not drop much at scale because concrete is a commodity — the material cost is flat. What changes is the contractor's willingness to negotiate on labor for larger jobs. For slabs over 1,000 sq ft, ask about volume discounts on labor. For patio-specific costs, see our patio cost guide.
Concrete Slab Cost by Size — Chart
The chart above shows how total project cost rises with slab area, using the midpoint of the 4-inch installed range. The key takeaway: the relationship is almost linear above 400 sq ft, meaning you can roughly estimate cost as area (sq ft) × $8 (national average per sq ft).
Below 400 sq ft, the estimate skews high because fixed costs (permit, site prep minimum, contractor day rate) do not shrink with size. A 10×10 slab might cost $600–$1,200, which is $6–$12/sq ft — the same unit rate as a 40×40 — but the total is small because the area is small.
Cost by Thickness at Each Size
Same size, different thickness
| Size | 3" | 4" | 5" | 6" |
|---|---|---|---|---|
| 10×10 (100 sq ft) | $500–$900 | $600–$1,200 | $700–$1,300 | $800–$1,500 |
| 20×20 (400 sq ft) | $2,000–$3,200 | $2,400–$4,800 | $2,800–$5,200 | $3,200–$6,000 |
| 30×40 (1,200 sq ft) | $6,000–$9,600 | $7,200–$14,400 | $8,400–$15,600 | $9,600–$18,000 |
Rule of thumb: each additional inch of thickness adds roughly 25% to concrete volume and 15–20% to total project cost.
Cost by Project Type at Each Size
20×20 ft (400 sq ft) by project type
| Project Type | Thickness | Reinforcement | Finish | Total |
|---|---|---|---|---|
| Shed Base | 4" | None | Broom | $2,400–$3,600 |
| Patio | 4" | Wire mesh | Broom | $2,400–$4,800 |
| Patio (stamped) | 4" | Wire mesh | Stamped | $4,000–$7,200 |
| Driveway | 5" | Rebar | Broom | $2,800–$5,200 |
| Garage Floor | 6" | Rebar + vapor barrier | Smooth trowel | $3,200–$6,000 |
Shed bases skip reinforcement because they carry no vehicle load. Patios add wire mesh. Stamped patios pay for extra crew time. Driveways thicken to 5" and switch to rebar. Garage floors add thickness, rebar, and a vapor barrier.
Why Small Slabs Cost More Per Square Foot
If you have read the tables above, you have noticed a pattern: a 10×10 slab costs the same $6–$12 per square foot as a 40×40. Here is why the per-square-foot price does not drop much:
- Contractor minimums. Most concrete contractors have a minimum job charge of $500–$1,000 regardless of size. On a 10×10 slab (100 sq ft), that minimum alone is $5–$10/sq ft.
- Equipment does not scale down. A concrete truck delivers a minimum of 1 cubic yard whether you need 1 or 10. Small jobs often pay for unused concrete.
- Setup time is fixed. A crew spends the same 1–2 hours setting forms for a 10×10 as for a 20×20. Labor efficiency only kicks in above about 400 sq ft.
When do you get a volume discount? Above 1,000 sq ft, contractors may discount labor by 10–20% because the crew stays on one site for multiple days instead of hopping between small jobs. Wondering whether to DIY at that size? See our DIY vs contractor breakdown.
How to Use the Size Chart for Your Project
- Find your size in the table above. If your planned size is not listed exactly, use the next larger size as a conservative estimate.
- Pick your thickness based on how you will use the slab: 4" for patios and shed bases (foot traffic only), 5" for driveways (passenger vehicles), and 6" for garages, workshops, or heavy vehicles.
- Plug your dimensions into the concrete slab cost calculator below. The tables give you a range — the calculator gives you a specific number based on your local price per cubic yard.
Frequently Asked Questions
How much does a 30×40 concrete slab cost?
A 30×40 slab (1,200 sq ft) costs $7,200–$14,400 at 4" thick. This is a common pole barn and workshop size. At 1,200 sq ft, ask your contractor about volume pricing — labor discounts often apply above 1,000 sq ft.
What size concrete slab is cheapest per square foot?
Slabs over 1,000 sq ft hit the lowest per-square-foot rates ($6–$8/sq ft in most regions) because fixed costs are fully amortized and crews work more efficiently on large, continuous pours.
Can I use the same price per square foot for any size?
Yes, as a rough estimate. $8/sq ft is a safe national average for a 4" slab at any size. But for very small slabs (under 200 sq ft), round up to $10–$12/sq ft to account for minimum charges. For exact pricing, use our calculator.
Get a Size-Specific Estimate Now
Tables give you a range. Enter your exact dimensions in our concrete slab cost calculator and get a line-by-line cost breakdown for your slab size — material, labor, site prep, and total. Free, no signup.
For the formula behind these tables, see how to calculate concrete slab cost.