Introduction
A concrete slab’s price tag is not just the concrete. The Concrete Slab Calculator gives you the volume — cubic yards or cubic meters — and from there you can price the material. But the full project cost also includes the gravel base, formwork, reinforcement, labor, and the finish on top. This guide breaks all five buckets down with real numbers, so a quote or a DIY budget never surprises you.
Prices below are typical US ranges and vary widely by region, season, and supplier — always get local quotes. Use them to understand the structure of slab costs and to sanity-check bids, not as final figures.
Open the Concrete Slab Calculator
The Five Cost Buckets
Every slab project, DIY or contractor-built, spends money in the same five places:
- Concrete — ready-mix by the cubic yard or bags by the pallet; usually the largest material cost.
- Base — compacted gravel or crushed stone under the slab, priced by the ton.
- Forms and reinforcement — lumber or metal forms, plus wire mesh or rebar.
- Labor — the crew’s time for excavation, forming, pouring, and finishing.
- Finish — broom, trowel, stamped, or exposed aggregate; finish upgrades add the most per-square-foot cost.
The volume drives bucket one; the square footage drives the rest. That’s why the calculator’s output is the starting point for every estimate in this guide.
What the Concrete Itself Costs
Ready-mix (delivered by truck) typically runs $130–$180 per cubic yard in the US, varying by region and mix design. Orders under about 3–4 yd³ usually attract a short-load fee of roughly $50–$150, because the plant sends a truck out partially full. A standard mixer carries 8–10 yd³ — a full load with no short-load fee.
Bagged concrete (80-lb bags) typically costs $5–$8 per bag at home centers, with each bag yielding about 0.6 ft³ (0.017 m³). Bags make sense up to roughly 1–2 yd³; beyond that, the per-yard cost climbs well above ready-mix and the mixing labor becomes brutal.
Worked example: driveway concrete cost
Take a driveway 40 ft × 12 ft × 5 in thick, with 10% waste. From the formula guide: 5 ÷ 12 = 0.4167 ft; 40 × 12 × 0.4167 = 200 ft³; ÷ 27 = 7.41 yd³; × 1.10 = 8.15 yd³.
At $150/yd³: 8.15 × 150 = $1,223 for the concrete, delivered — and at 8.15 yd³ it’s nearly a full truckload, so no short-load fee. The metric cross-check: 12.19 m × 3.66 m × 12.7 cm = 5.66 m³; × 1.10 = 6.23 m³; 6.23 × $197/yd³-equivalent… simpler: 6.23 m³ × 1.308 = 8.15 yd³. Same number, same $1,223.
Base, Forms, and Reinforcement
The base is not optional — 4–6 in (10–15 cm) of compacted gravel spreads the load and stops the slab settling into soft soil. Gravel runs roughly $30–$60 per ton delivered, and a cubic yard weighs about 1.4 tons.
For that 40 × 12 ft driveway with a 5-in base: 480 ft² × (5 ÷ 12) = 200 ft³ = 7.41 yd³ of gravel; × 1.4 = 10.4 tons; at $45/ton ≈ $467. (Order gravel by the ton from a landscape supplier — it’s a separate delivery from the concrete.)
Forms: 2×6 lumber for a 5–6 in slab (2×4 for a 4-in slab), plus stakes — typically $100–$300 in lumber for a residential slab, reusable if you’re careful. Reinforcement: a 5 × 10 ft sheet of 6×6 wire mesh runs roughly $15–$30; rebar for a driveway grid (say #4 at 18-in spacing) adds roughly $200–$400 in steel. Mesh vs rebar selection is covered in the material guide.
Labor and Finish Costs
Contractors typically price plain residential slabs at $6–$10 per square foot installed (4-in patio or walkway, broom finish), $8–$12 per square foot for 5–6 in driveways and garage floors. That per-foot price bundles excavation, base, forms, concrete, labor, and a basic finish. Decorative finishes cost more:
| Finish | Typical add-on over plain (per sq ft) |
|---|---|
| Broom finish (standard, slip-resistant) | Included in base price |
| Smooth trowel (garage interiors) | $0.50–$1.50 |
| Exposed aggregate | $2–$4 |
| Stamped / decorative pattern | $4–$10 |
Finishes are where DIY savings are smallest and contractor skill matters most — a broom finish is forgiving; stamped work is not. The DIY vs pro guide breaks down where your labor actually pays.
Example Project Budgets
Putting the buckets together — material costs are DIY (your labor free), installed prices are contractor turnkey:
| Project | Concrete volume (10% waste) | DIY materials (approx.) | Pro installed (approx.) |
|---|---|---|---|
| Shed base 10 × 8 ft, 4 in | 1.09 yd³ (49 bags) | $400–$550 | $700–$1,000 |
| Patio 20 × 12 ft, 4 in | 3.26 yd³ | $850–$1,100 | $1,700–$2,400 |
| Driveway 40 × 12 ft, 5 in | 8.15 yd³ | $1,900–$2,400 | $3,800–$5,800 |
| Garage 24 × 24 ft, 5 in | 9.78 yd³ | $2,200–$2,800 | $4,600–$6,900 |
Check the shed-base math: 10 × 8 × (4 ÷ 12) = 26.67 ft³; × 1.10 = 29.33 ft³; ÷ 0.6 = 48.9 → 49 bags; at $6.50/bag = $319, plus ~$80 of gravel and $40 of lumber ≈ $440 in materials. And the garage: 24 × 24 × (5 ÷ 12) = 240 ft³ = 8.89 yd³; × 1.10 = 9.78 yd³; × $150 = $1,467 for concrete alone.
What Moves the Price
- Thickness. Each extra inch on a 480 ft² driveway adds 40 ft³ — about 1.5 yd³, or $220+ of concrete. Don’t upsize thickness “just in case” without a reason; do follow code minimums (see the code compliance guide).
- Access. If the truck can’t reach the forms, you’ll pay for a pump ($500–$1,000+) or wheelbarrow labor.
- Excavation. Removing soil and hauling it away can add several hundred dollars; rocky or sloped sites cost more.
- Season. Concrete prices and crew availability tighten in peak building season; winter pours may need blankets and accelerators.
- Demolition. Tearing out an old slab first roughly doubles the labor portion — get it quoted separately.
Related Guides
- Complete Slab Guide — the full walkthrough of slab estimating.
- Estimating Guide — step-by-step slab measurement.
- DIY vs Hiring a Pro — where your labor actually saves money.
- Concrete Slab Calculator FAQ — quick cost and volume answers.
- Pour-Day Checklist — verify everything before the truck arrives.
Price It Out
Start with volume from the Concrete Slab Calculator, multiply by your local per-yard rate, add base gravel, forms, and reinforcement, then decide whether the labor savings of DIY justify the work. Get at least two ready-mix quotes and two contractor bids — slab pricing varies enough by market that a single quote is never the full picture.
Disclaimer: Prices in this guide are typical US ranges for planning purposes and vary by region, season, and supplier. Calculator results are planning estimates based on the dimensions you enter. Verify volumes and rates with local suppliers, check local building codes for thickness and setback requirements, and consult a licensed professional for structural or code-related decisions.
