Quantity · Ready-mix order
Ready Mix Concrete Calculator
Convert slab dimensions to cubic yards for a ready-mix order — with waste, quarter-yard rounding, and a short-load warning before you call the plant.
Pour dimensions
Order this many yards
3.25cy
Rounded up in ¼ cy steps from 3.11 cy with waste
- Raw volume
- 2.96 cy
- With waste
- 3.11 cy
- Area
- 240 sq ft
Short load: under 4 cy. Plants often add $50–150. Confirm when you call.
Material only (delivered)
$473–$800
Ready-mix $130–200/cy + short-load surcharge. Labor and forms not included — use the cost calculator for installed totals.
Breakdown
- 20 × 12 × (4 ÷ 12) = 80 cu ft
- ÷ 27 = 2.96 cy raw
- × (1 + 5%) = 3.11 cy
- Round up to 3.25 cy
Price data updated . National US ranges from published supplier and contractor averages. Not a bid. Local quotes vary.
How ready-mix yardage is calculated
Ready-mix is sold by the cubic yard. Get the volume right first; price and labor come second.
cu ft = length_ft × width_ft × (thickness_in ÷ 12) cu yd = cu ft ÷ 27 with waste = cu yd × (1 + waste %) order yards = ceil(with waste × 4) ÷ 4 ← ¼ cy steps
Worked example. A 20 × 12 ft × 4 in slab is 80 cu ft → 2.96 cy. With 5% waste → 3.11 cy, rounded to 3.25 cy for the plant. That sits above the 4 cy short-load line, so you avoid the small-order surcharge — unlike a tiny pad pour.
Ready-mix order checklist
What to confirm when you phone the batch plant — the details ranking calculators usually skip.
| Ask the plant | Typical US note |
|---|---|
| Mix strength (psi) | 3000–4000 psi common for residential slabs; follow local code |
| Slump | ~4 in typical for slabs; higher for pumped mixes |
| Air entrainment | Exterior freeze-thaw exposure usually needs entrained air |
| Short-load fee | $50–150 under ~4 cy |
| Delivery / wait time | Extra charges if the truck sits past the free unload window |
| Price per cy delivered | National planning range $130–200/cy — get a local quote |
Ready mix concrete calculator FAQ
- How do I calculate ready-mix concrete in cubic yards?
- Multiply length × width × (thickness in inches ÷ 12) to get cubic feet, then divide by 27. Add a waste percentage (often 5%) so you do not run short mid-pour. Plants commonly take orders in quarter-yard steps — this calculator rounds up to the next 0.25 cy.
- What is a short load of ready-mix?
- A short load is an order under about 4 cubic yards. The plant still dispatches a truck, so many charge a $50–$150 surcharge. Combine pours on one day or use bags when the volume is tiny.
- How much extra ready-mix should I order?
- Five percent covers most rectangular slabs with a decent subgrade. Bumpy excavation, thick edges, or first-time pours may need closer to 10%. Running short costs more than a leftover wheelbarrow load — leftover can become a pad or pier.
- When should I use bags instead of ready-mix?
- Below roughly 1 cubic yard, bagged concrete (Sakrete / Quikrete) is usually cheaper and easier once short-load fees are counted. Above that, a truck saves labor. Use the bag calculator to compare.
- Does this include labor to place the concrete?
- No. This page sizes the truck order and shows a delivered-material range only. For installed cost with labor, rebar, and forms, open the concrete cost calculator.
Next: price the pour or switch to bags
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