Ready Mix Calculator
A ready mix calculator converts your slab, footing, or column dimensions into cubic yards of concrete to order from a ready mix truck. This calculator handles slabs, continuous footings, cylindrical columns (Sonotube), and stair pours, applies a waste factor for spillage and uneven grade, and estimates the delivered ready mix cost including short-load fees. It also shows the equivalent number of 60 lb and 80 lb bags if you're considering DIY bagged concrete instead.
How the Ready Mix Calculator Works
The ready mix calculator converts your pour dimensions to cubic yards:
- Rectangular pours (slab, footing, stair): length x width x thickness (in feet)
- Cylindrical pours (column, Sonotube): pi x radius^2 x height
Then:
- Cubic yards = cubic feet / 27
- Apply 10-20% waste factor for spillage, over-dig, and uneven grade
- Round up to the nearest 0.25 cubic yard (typical ready mix order increment)
Common Ready Mix Pours
| Pour | Dimensions | Cubic Yards |
|---|---|---|
| 10x10 4 in slab | 100 sqft, 4 in | 1.23 yd |
| 20x20 4 in slab | 400 sqft, 4 in | 4.94 yd |
| 24x24 garage slab | 576 sqft, 4 in | 7.11 yd |
| Driveway 12x50 6 in | 600 sqft, 6 in | 11.11 yd |
| Footing 1.5 ft x 1 ft x 50 ft | standard | 2.78 yd |
| 10 in Sonotube x 4 ft | 18 columns for deck | 6.55 yd |
Ready Mix Concrete Price (2025)
Ready mix concrete price ranges $130-175 per cubic yard for 3,000 PSI in 2025, depending on region and volume. Pricing structure:
- Base: $130-155/yd for 3,000 PSI standard mix
- Each 500 PSI above 3,000: adds $5-10/yd
- Short-load fee: under 5 yd adds $15-30/yd, under 3 yd adds $30-50/yd
- Delivery trip fee: $100-150 per truck
- Saturday / overtime: $50-100 surcharge
- Long pours (slow unload over 45 min): $50-100/truck
A typical 10 yd pour of 3,500 PSI for a driveway costs $1,500-1,900 delivered. A 3 yd short load for a patio costs $625-775 delivered (disproportionately expensive per yard).
Ready Mix Truck Volume
A standard ready mix truck holds 8-11 cubic yards. Small mini-mixers hold 4-6 yd. Concrete must be placed within 90 minutes of leaving the batch plant (cement starts hydrating immediately). If your pour takes longer than one truck can deliver, schedule two trucks 30-60 minutes apart.
Ready Mix vs Bagged Concrete Cost
When to use ready mix vs bags:
- Ready mix: cheaper per cubic yard above 1-2 yd total. Always cheaper for pours over 5 yd.
- Bags: easier for very small pours (under 0.5 yd), fence posts, small repairs. $6 per 80 lb bag at Home Depot. One 80 lb bag = 0.6 cubic feet. To match 1 cubic yard, you need 45 bags = $270 vs $230-250 for 1 yd delivered.
For anything over 1 yard, ready mix beats bags on both cost and labor.
Ready Mix PSI Guide
Use the right PSI for the pour:
| PSI | Application | Price Premium |
|---|---|---|
| 2,500 | Fill, non-structural | -$5/yd |
| 3,000 | Interior slab, patio | baseline |
| 3,500 | Driveway, garage slab | +$8/yd |
| 4,000 | Foundation wall, footing | +$15/yd |
| 5,000 | Structural column, heavy load | +$25/yd |
Slab Thickness Guidelines
- Patio / walkway: 3-4 in
- Residential floor: 4 in
- Driveway: 4-6 in (6 in for heavy vehicles or clay soil)
- Garage slab: 4-6 in
- Commercial slab: 6-8 in minimum, rebar or mesh
- Footings: 8-16 in depth, below frost line (24-48 in in cold climates)
Placing the Order
When ordering ready mix:
- Call 2-3 days ahead (1 week for large orders)
- Tell them the exact PSI, slump (typically 4-5 in for residential), and additives (air entrainment for freeze-thaw, fiber for cracking control)
- Give them an accurate yardage - under-ordering forces a second trip fee
- Prepare the site: forms set, rebar in place, gravel base compacted
- Have 2-3 strong helpers ready to place, screed, and float immediately
Waste Factor Guidance
- Slab on flat gravel base: 5-10% waste
- Footing with uneven trench: 15-20%
- Multiple columns or piers: 10% per column
- Curbing or complex pours: 15%
Never under-order. Running out of concrete mid-pour requires calling for a second (expensive) truck or abandoning the pour.