Concrete Slab Cost Calculator
Installed cost for a 4–6″ slab on grade: ready-mix by the yard, a delivery or short-load fee, and a flatwork crew by the square foot. Base stone, rebar and excavation are extra — see the FAQs.
Order 4.75 yd³ ready-mix — plants ticket in ¼-yd³ and most charge a short-load fee under ~5 yd³.
- Net volume (113.3 ft³)
- 4.20 yd³
- Waste 10%
- + 0.42 yd³
- Ready-mix ticket
- 4.75 yd³
- Approx. weight
- 17,000 lb
- 80 lb bags
- 208
- 60 lb bags
- 278
- 40 lb bags
- 416
Quantities follow the ticket. Links may earn us a commission at no cost to you; they never change a number.
Get 3 quotes for this concrete job
The estimate above is a national range. A local concrete & masonry contractor who sees your site can give you a firm price, and comparing 3 bids is the single biggest lever on what you pay. Tell us where the job is and we will match you with up to 3 contractors who serve your ZIP.
- Your quantities and this estimate go with the request, so you are not starting over.
- No account, no app. Contractors call or text you directly.
- One request. We do not resell your details beyond the matched contractors.
How to calculate concrete by hand
Cubic yards = Length (ft) × Width (ft) × Thickness (in) ÷ 12 ÷ 27 · 80 lb bags = ft³ ÷ 0.60
Worked example
- Area: 20 ft × 17 ft = 340 ft².
- Volume: 340 ft² × (4 in ÷ 12) = 113.3 ft³ = 4.20 yd³.
- Waste 10%: 113.3 × 1.10 = 124.7 ft³ = 4.62 yd³ → ready-mix ticket 4.75 yd³.
- Bags instead: 124.7 ÷ 0.60 = 208 × 80 lb bags (or 277 × 60 lb, 416 × 40 lb).
- Above 1 yd³, ready-mix costs less than bags even with a short-load fee — order the truck.
- 1 yd³ of concrete
- 45 × 80 lb · 60 × 60 lb · 90 × 40 lb bags
- 1 yd³ at 4″ thick
- ≈ 81 ft²
- 1 yd³ at 6″ thick
- ≈ 54 ft²
- 80 lb bag yield
- 0.60 ft³ · ≈ 1.8 ft² at 4″
How we price this
The low, typical and high columns are the 20th, 50th and 80th percentile of published us national averages for ready-mix 3,000 psi, delivery and labor. They are estimates for budgeting, not quotes — enter your own supplier and crew prices above to replace them. Ranges are re-checked monthly; see the methodology page for how every number on this site is derived.
- HomeAdvisor cost guides — ready-mix per yard, slab installed $/ft²
- NRMCA industry data — ready-mix pricing context
- Home Depot / Lowe’s bag pricing — 80/60/40 lb bag prices
Questions crews ask
How much does a concrete slab cost per square foot?
$6–$12 per ft² installed for a 4″ slab with mesh and a broom finish; $8–$14 for 6″ with rebar. A 20 × 17 ft (340 ft²) patio runs $2,000–$4,000. Materials are about a third of that; labor the rest.
How much is a yard of concrete delivered?
$125–$180 per cubic yard for 3,000–4,000 psi ready-mix, plus a short-load fee of $75–$150 for orders under 4–5 yards. Fibre, accelerators and winter heating add $5–$15 per yard each.
What else do I need to budget for a slab?
Excavation and grading ($1–$2 per ft²), 4″ of compacted stone base ($0.50–$1 per ft²), wire mesh or rebar ($0.50–$1.50 per ft²), forms, vapour barrier under interior slabs, and a saw-cut or tooled control joints. Pumping adds $600–$900 if the truck cannot reach.