Concrete Slab Cost Calculator
How much does it cost to pour a concrete slab? This concrete slab cost calculator prices a full poured-slab project — patio, equipment pad, shed foundation or garage floor — from the ground up: slab dimensions, 4″/6″ thickness, concrete PSI, gravel base, excavation, wire mesh or rebar reinforcement, finish (broom, stamped, exposed aggregate, stained), your region, and labor. You get a line-item breakdown — concrete in cubic yards, site prep, reinforcement, forms, finish, labor — plus a low–high range and cost per square foot, so you can sanity-check any contractor quote. The Volume tab answers the pure material question (cubic yards, 80-lb bags, truck loads), and the DIY vs Pro tab shows what you would really save doing it yourself.
Concrete Slab Cost Estimator
Estimates the installed cost of a poured concrete slab, patio or pad. All prices are editable defaults based on 2026 US market data (see Sources) — adjust them to your local quotes. Project presets fill in typical sizes; you can override everything.
Site prep
Prices (editable)
Concrete Volume & Bag Calculator
Pure material math for the slab: cubic yards to order, 80-lb bags, and ready-mix truck loads. Same inputs as the Cost Estimator.
Need the full material takeoff (rebar grid, wire mesh, forms) instead of just volume? Try the concrete calculator for bags + rebar quantities.
DIY vs Pro Comparison
DIY swaps the contractor’s pour-and-finish labor for your own time plus about $200 in tool rentals (plate compactor, screed, wheelbarrows). Materials, site prep, reinforcement and forms cost the same either way.
What Drives the Cost of a Poured Concrete Slab?
A poured concrete slab usually lands between $6 and $12 per square foot installed in 2026, with an average residential project totaling $3,000–$6,000. The calculator above breaks the total into seven pieces, because each one is negotiable in a different way:
- Concrete itself — ready-mix runs $120–$180 per cubic yard delivered; our $145/yd default sits in the middle. Concrete is priced by volume, and volume comes from the slab math: length × width × (thickness ÷ 12) ÷ 27 = cubic yards. Going from 4 in to 6 in adds about 50% more concrete. Batch plants round orders to half-yards, so a 2.18-yard slab becomes a 2.5-yard order — the waste you cannot sell back.
- Thickness — 4 inches is standard for patios and equipment pads; 6 inches if vehicles will drive over it or loads are heavy. Thicker also means more gravel, more labor and more time on the truck.
- Strength (PSI) — 3,000 PSI is fine for a patio; 3,500–4,000 PSI for slabs that see vehicles or freeze-thaw. Higher strength adds roughly $8–$15 per yard.
- Site prep — excavation/grading (~$1.50/sq ft in this model) plus a 4-inch compacted gravel base. The base is not optional in any climate with frost: it drains water away from the slab so the ground does not heave. Skipping prep is the most common way a cheap bid becomes an expensive repair.
- Reinforcement — wire mesh ($0.45/sq ft) controls cracking from shrinkage; rebar grid ($0.85/sq ft) is stronger for vehicle slabs; fiber additive (~$12/yard) mixes crack control straight into the concrete.
- Finish — a broom finish is the baseline ($0 extra). Colored (+$2.50), exposed aggregate (+$3.50), stamped (+$6.00) and stained (+$9.00) are priced per square foot because they mostly buy skilled labor time, not materials.
- Labor and region — pour-and-finish labor averages about $3.50/sq ft and swings roughly ±20% by region (South cheapest, West/Northeast dearest). Most contractors also carry a $1,000–$1,500 minimum charge, which is why small pads look expensive per square foot — the model applies a $1,000 minimum to the pro total.
Typical slab costs by thickness (12 × 14 ft patio, Midwest, 4-in gravel base)
| Thickness | Concrete (yd³) | Total | $/sq ft |
|---|---|---|---|
| 4 in (standard patio) | 2.5 | $1496.50 | $8.91 |
| 6 in (heavy use) | 3.5 | $1641.50 | $9.77 |
What finish adds (20 × 20 ft slab, 4 in, Midwest)
| Finish | Adder /sq ft | Total |
|---|---|---|
| Broom / plain | $0.00 | $3497.65 |
| Colored | $2.50 | $4497.65 |
| Exposed aggregate | $3.50 | $4897.65 |
| Stamped | $6.00 | $5897.65 |
| Stained | $9.00 | $7097.65 |
Same slab, different region (20 × 20 ft, 4 in, broom finish)
| Region | Multiplier | Total |
|---|---|---|
| South | 0.90× | $3275.65 |
| Midwest | 1.00× | $3497.65 |
| Northeast | 1.15× | $3830.65 |
| West | 1.20× | $3941.65 |
Tables computed live from the same engine as the calculator — same inputs, same results.
Worked Example 1: 12 × 14 ft Patio, 4 in, Midwest
- Area & volume. 12 × 14 = 168 sq ft. 168 × (4/12) ÷ 27 = 2.07 yd³; +5% waste = 2.18 → order 2.5 yd³.
- Concrete. 2.5 × $145 = $362.50.
- Gravel base. 168 × (4/12) ÷ 27 = 2.07 yd³ × 1.35 ton/yd³ = 2.80 tons × $45 = $126.00.
- Excavation. 168 × $1.50 × 1.00 = $252.00.
- Wire mesh. 168 × $0.45 = $75.60. Forms: 168 × $0.55 = $92.40. Broom finish: $0.
- Labor. 168 × $3.50 × 1.00 = $588.00.
- Total: $1496.50 (range $1272.03–$1720.98), i.e. $8.91/sq ft — inside the published $6–$12 band for plain poured slabs.
Worked Example 2: 20 × 20 ft Slab, 6 in, Stamped, West
- Area & volume. 20 × 20 = 400 sq ft. 400 × (6/12) ÷ 27 = 7.41 yd³; +5% = 7.78 → order 8.0 yd³.
- Concrete (4,000 PSI). 8.0 × ($145 + $15) = $1280.00.
- Gravel base 4 in: $300.15. Excavation (×1.20 region): $720.00.
- Rebar grid: 400 × $0.85 = $340.00. Forms (×1.20): $264.00.
- Stamped finish: 400 × $6.00 = $2400.00. Labor (×1.20): $1680.00.
- Total: $6984.15, i.e. $17.46/sq ft — inside the published $12–$18 band for stamped concrete.
Site Prep, Permits & Curing: Practical Tips
- Compact the base in lifts. Add gravel in 2-inch lifts and compact each with a plate compactor. A loose base settles unevenly and the slab follows it — cracking within a season.
- Form it straight and level. Cheap lumber forms and a string line beat fancy tools. Slope the slab 1/4 in per foot away from the house or shed so water drains off.
- Control joints every 8–12 ft. A common rule is joint spacing in feet ≈ 2–2.5× thickness in inches (a 4-in slab: joints every 8–10 ft). Concrete will crack; joints decide where.
- Do you need a permit? Usually yes for slabs over ~120 sq ft, attached to a structure, or in a floodplain/setback zone — but it varies by city. Call your building department before you order concrete; many patios under 120 sq ft need nothing.
- Curing. Keep the slab moist (or covered with a curing compound) for the first 7 days; stay off it 24–48 hours, no vehicles for 7 days. Full strength takes ~28 days.
- Weather. Do not pour on frozen ground or when temperatures will drop below freezing within 48 hours. In summer, an early-morning pour and a sunshade buy you working time.
- Quote comparison. Ask every contractor for the same spec: thickness, PSI, base depth, reinforcement, finish. A $2,000 cheaper bid often means 3 in instead of 4, or no base.
How is this different from our other concrete tools?
This tool = project cost. It prices the whole job — concrete + site prep + reinforcement + forms + finish + labor — for slabs, patios and pads.
- Concrete calculator = materials only (volume in yd³, 80-lb bags, rebar quantities). No labor, no prices, no site prep.
- Concrete driveway cost calculator = cost estimator for driveways (linear footprints, vehicle-load specs, driveway removal). This tool covers slab/patio/pad footprints instead.
- Paver calculator = dry-laid pavers (paver counts, base layers, laying patterns). Poured concrete is a completely different job.
Concrete Slab Cost FAQs
How much does it cost to pour a concrete slab?
For a typical 12 × 14 ft patio (168 sq ft) at 4 inches thick with wire mesh, a 4-in gravel base and a broom finish in the Midwest, this calculator estimates $1,496.50 (range $1,272.03–$1,720.98), or $8.91 per square foot. That sits inside the published 2026 band of $6–$12 per square foot for plain poured slabs. An average residential slab project runs $3,497.65 (our 20 × 20 ft, 4-in example), inside the published $3,000–$6,000 project range. Try the Cost Estimator tab above with your own dimensions, thickness and finish — it prices any slab, not just the example.
How much does a concrete patio cost?
The same math prices a patio: a 12 × 14 ft concrete patio at 4 inches thick estimates $1,496.50 installed in the Midwest ($8.91/sq ft), including 2.5 cubic yards of concrete ($362.50), 2.80 tons of gravel base ($126.00), excavation ($252.00), wire mesh ($75.60), forms ($92.40) and pour-and-finish labor ($588.00). Concrete patio cost per square foot runs higher with stamped or exposed finishes — stamped adds $6.00/sq ft. Use the calculator to swap finishes and see the difference instantly.
How much does a 20×20 concrete slab cost?
A plain 20 × 20 ft slab (400 sq ft) at 4 inches with broom finish estimates $3,497.65 in the Midwest ($8.74/sq ft). The same slab at 6 inches thick with rebar, 4,000 PSI concrete and a stamped finish in the West estimates $6,984.15 ($17.46/sq ft) — thickness, finish and region roughly double the job. That is why per-square-foot quotes are misleading: always compare itemized specs (thickness, PSI, base, reinforcement, finish).
What is the average cost of a concrete pad?
A small 10 × 10 ft concrete pad (for a shed or AC unit) estimates $1,000.00 — the math only comes to $847.65 but the model applies the common $1,000 contractor minimum charge. Small pads look expensive per square foot precisely because of minimums: most contractors will not mobilize for less than $1,000–$1,500. A 10 × 10 pad is one of the few jobs where DIY realistically beats the minimum charge (see the DIY vs Pro tab).
How many cubic yards of concrete do I need for a slab?
Volume = length × width × (thickness ÷ 12) ÷ 27. A 12 × 14 ft slab at 4 inches is 168 × (4/12) ÷ 27 = 2.07 yd³ theoretical; add ~5% waste and round up to the half-yard (batch plants do not sell fractions below that), so order 2.5 yd³. That is also 98 80-lb bags if you mix by hand — but anything over ~1 yd³ is usually cheaper and far less work as ready-mix. The Volume tab above does this math with your dimensions.
How much does stamped concrete cost per square foot?
Stamped finish adds $6.00/sq ft to a plain slab in this calculator. Our 20 × 20 ft, 6-in slab example with stamped finish in the West totals $6,984.15, or $17.46 per square foot — inside the published $12–$18 band for stamped concrete. Stamping pays for pattern mats, release agents, color and the skilled labor to imprint before the concrete sets; it is one of the hardest finishes to DIY.
Is it cheaper to pour concrete yourself (DIY)?
Yes, if you have the crew: for the 20 × 20 ft example, DIY estimates $2,297.65 versus $3,497.65 pro — a saving of $1,200.00 (34.31%). DIY keeps the same material costs and adds ~$200 in tool rentals (plate compactor, screed, wheelbarrows); what you skip is the $1,400.00 of pour-and-finish labor. The catch: concrete waits for no one. Small pads are realistic DIY; slabs over ~400 sq ft or stamped finishes usually justify a crew.
Do I need a permit to pour a concrete slab?
Often yes for slabs over roughly 120 sq ft, anything attached to a structure, or work in a floodplain or setback zone — but rules vary by city and county. Call your local building department before ordering concrete; many small detached patios need no permit at all. If you hire a pro, permits are normally their job — confirm it is in the quote.
How thick should a concrete patio be?
4 inches is standard for patios and light pads. Go 6 inches if vehicles will drive on it (RV pad, garage approach) or loads are heavy. Our thickness table shows a 12 × 14 ft patio costs $1,496.50 at 4 in versus $1,641.50 at 6 in — about 10% more here, since labor, forms and prep do not scale linearly with concrete volume.
How long does a concrete slab take to cure?
Keep the slab moist (or use a curing compound) for the first 7 days; stay off it for 24–48 hours and keep vehicles off for 7 days. Concrete reaches design strength at ~28 days. Never pour on frozen ground or when a freeze is expected within 48 hours — frozen concrete loses strength permanently.
How much gravel base goes under a concrete slab?
4 inches of compacted gravel is the standard recommendation (6 in on soft soil). For the 12 × 14 ft patio that is 2.80 tons ($126.00 at $45/ton). Compact it in 2-in lifts with a plate compactor — a loose base settles and the slab cracks with it. Skipping the base entirely saves $126.00 here but is the most common cause of frost-heave damage.
Slab vs driveway vs pavers: which calculator do I need?
This tool prices slab, patio and pad footprints (area-based, with gravel base and reinforcement). A concrete driveway cost calculator is the right one for linear driveway footprints and driveway removal. For material quantities only (cubic yards, 80-lb bags, rebar), use the concrete calculator. And if you are laying dry pavers instead of pouring concrete, that is a different job entirely — use the paver calculator.
Sources
- 2026 US contractor pricing surveys: poured slab $6–$12/sq ft installed; ready-mix concrete $120–$180/cubic yard; stamped concrete $12–$18/sq ft; average residential slab project $3,000–$6,000.
- Base gravel density 2,700 lb/yd³ (1.35 ton/yd³): aggregate producer data sheets (consistent with RF Cafe bank/torpedo rock figures).
- Curing guidance: ACI 308 — 7-day moist cure; vehicle traffic after 7 days; design strength at ~28 days. Control-joint spacing rule of thumb: 2–2.5× slab thickness (inches → feet).
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