Concrete
How Many Yards of Concrete Are in a Truck?
A ready-mix concrete truck carries 8 to 12 cubic yards; because of road weight laws, a typical truck mixer carries 9 to 11 cubic yards, according to the National Ready Mixed Concrete Association.
By Kumar Baniya, MEng in Structural Engineering (University of Leeds) · Published
How many yards does a concrete truck hold?
8 to 12 cubic yards, with 9 to 11 yd³ being the typical load. The National Ready Mixed Concrete Association (NRMCA) gives these figures in its guidance on ordering ready-mixed concrete. Your supplier’s trucks and your state’s weight limits decide the exact load.
Why can’t a truck carry a full drum?
Fresh concrete is heavy, and a loaded truck mixer has to stay within road weight laws. That limit — not the size of the drum — usually caps the load, which is why most trucks carry less than the drum could physically hold.
How many truckloads will my pour need?
Divide the volume you are ordering by the load your supplier sends per truck, and round up. At typical load sizes:
| Order | Trucks at 9 yd³ | Trucks at 10 yd³ | Trucks at 11 yd³ |
|---|---|---|---|
| 6 yd³ | 1 | 1 | 1 |
| 12 yd³ | 2 | 2 | 2 |
| 20 yd³ | 3 | 2 | 2 |
| 30 yd³ | 4 | 3 | 3 |
| 45 yd³ | 5 | 5 | 5 |
Ask the supplier how they will split the order: the last truck may carry only the remainder.
What about small pours?
Suppliers can set a minimum order or a charge for loads below a set size, which can make a very small pour cost more per yard. Get the minimum and any small-load charge from your supplier, then compare with bagged mix — the concrete calculator shows both side by side. For bag counts, see how many bags of concrete are in a yard.
How many trucks for a 40 × 30 slab?
A 40 × 30 ft slab 6 in thick is 40 × 30 × 6 ÷ 324 = 22.22 yd³. Adding 5% for contingencies — inside NRMCA’s suggested 4% to 10% — gives 23.33 yd³, which is 3 trucks at 10 yd³ or 3 at 9 yd³. Thickness and the contingency percentage here are examples; your plans and supplier decide the real figures.
What is the 90-minute rule for ready-mix concrete?
ASTM C94, the standard specification for ready-mixed concrete cited in NRMCA’s ordering guidance, calls for concrete to be discharged at the job site within 90 minutes and before 300 drum revolutions after water is added to the cement. Plan access and crew so each truck can unload promptly.
Related calculations
Work out the volume first with how to calculate yards of concrete. NRMCA also suggests ordering 4% to 10% more than the plan volume to cover contingencies.