Updated July 1, 2026
How much does the concrete for a slab cost in 2026?
The concrete for a 10 by 10 ft slab poured 4 inches thick costs about $401 in bagged mix in 2026, which is 62 eighty-pound bags at $6.47 per bag with 10 percent waste included. A 20 by 20 ft slab at the same thickness needs 5.43 cubic yards, or about $1,585 in bags. Above roughly one cubic yard, delivered ready-mix usually beats bags on price, so treat the bag figures below as the DIY ceiling.
Concrete volume and material cost by slab size
| Slab size | Thickness | Cubic yards (10% waste) | 80 lb bags | Bagged cost at $6.47/bag |
|---|---|---|---|---|
| 10 x 10 ft | 4 in | 1.36 | 62 | $401 |
| 10 x 10 ft | 6 in | 2.04 | 92 | $595 |
| 12 x 12 ft | 4 in | 1.96 | 89 | $576 |
| 12 x 12 ft | 6 in | 2.93 | 132 | $854 |
| 16 x 20 ft | 4 in | 4.35 | 196 | $1,268 |
| 16 x 20 ft | 6 in | 6.52 | 294 | $1,902 |
| 20 x 20 ft | 4 in | 5.43 | 245 | $1,585 |
| 20 x 20 ft | 6 in | 8.15 | 367 | $2,374 |
| 24 x 24 ft | 4 in | 7.82 | 353 | $2,284 |
| 24 x 24 ft | 6 in | 11.73 | 528 | $3,416 |
Download the full table as CSV, including 60 lb bag counts and exact costs. Going from 4 to 6 inches adds 50 percent more concrete on every row, which is why garage floors cost so much more than patios of the same footprint.
Methodology
Every figure is computed from the same formula our Concrete Calculator uses: volume equals length times width times thickness converted to feet, increased by a 10 percent waste factor for spillage and uneven subgrade, then divided by 27 to get cubic yards. Bag counts round the waste-adjusted volume up to whole bags using the published yields of 0.60 cubic feet per 80 lb bag and 0.45 cubic feet per 60 lb bag from the Quikrete Concrete Mix data sheet. The cost column multiplies the 80 lb bag count by $6.47, the listed price for a standard 80 lb bag of Quikrete Concrete Mix at both Home Depot and Lowe's, checked July 1, 2026. Bag prices vary by store and region, so treat the cost column as a national baseline rather than a quote.
These are material costs for the concrete alone. They exclude gravel base, forms, reinforcement, and labor, and they price bagged mix rather than delivered ready-mix, which ran about $125 to $195 per cubic yard through 2025 and 2026 per HomeGuide and is usually the cheaper route above one cubic yard. Sources: Quikrete Concrete Mix data sheet, Home Depot listing, Lowe's listing, HomeGuide concrete prices. This table is refreshed annually and whenever bag prices move materially.
Cite this page
ConcreteCalcTools, "Concrete Slab Cost by Size (2026)," https://concretecalctools.com/concrete-slab-cost-2026, updated July 1, 2026.
Run your own numbers
- Concrete Calculator for any slab size, thickness, and waste factor
- Cubic Yard Calculator for volumes measured in inches
- Rebar Calculator for the reinforcement grid under the slab