Concrete Slab Cost Calculator
This concrete slab cost calculator estimates the cost to pour a concrete slab. Enter the slab’s length, width, and thickness, keep or edit the pre-filled US-average prices, and it returns an itemized total — material, delivery, and finishing labor — with a low–mid–high range. It also shows the slab’s volume and a bag-vs-ready-mix comparison.
How to use this calculator
- Enter the slab length, width, and thickness.
- Edit the concrete and labor prices to match your area or a contractor quote.
- Keep finishing labor ticked for an installed price, or untick it for material-only.
- Read the itemized total and the low–mid–high range.
What drives the cost to pour a slab
The concrete itself is the smaller part of a finished slab. At about 4 inches thick a slab uses roughly 0.012 cubic yards per square foot, so the material runs only about $2 per square foot. The rest of an installed price — commonly $5–10 per square foot — is labor: excavating and compacting the base, setting forms, placing and screeding the concrete, floating and finishing the surface, and adding rebar or wire mesh.
Thickness matters too. Stepping a slab from 4 to 6 inches adds 50% more concrete and more labor. Edge thickening, a special finish, and poor site access all push the number higher, which is why this calculator gives a range rather than a single figure.
Slab cost reference (US averages)
National averages as of 2025, used as the calculator defaults. Confirm against local prices.
| Item | Typical price |
|---|---|
| Ready-mix, delivered | $160 / yd³ |
| Finishing labor | $2–$8 / ft² |
| Concrete only (4″ slab) | ≈ $2 / ft² |
| Installed slab (typical) | $5–10 / ft² |
Need just the volume? Use the concrete slab calculator. For other pours, try the driveway cost calculator, the pad cost calculator, or the general concrete cost calculator.
Frequently asked questions
How much does it cost to pour a concrete slab?
A finished concrete slab typically costs $5–10 per square foot installed, depending on thickness, reinforcement, finish, and site access. The concrete material alone is about $2 per square foot at 4 inches thick.
How much does a 20x20 concrete slab cost?
A 20 × 20 ft slab (400 sq ft) at 4 inches is about 4.9 cubic yards of concrete, roughly $800 in material plus delivery. Finished with labor it commonly runs $2,000–4,000. Enter your prices above for a tailored estimate.
What affects the cost of a slab the most?
Thickness, square footage, and finishing labor drive the price. Rebar or wire mesh, a thicker edge, a special finish, and difficult access all add cost on top of the concrete itself.
Should I get ready-mix or bags for a slab?
Most slabs above half a cubic yard are cheaper and faster with ready-mix delivery. The calculator shows the bag count and bag cost so you can compare against a delivered price.