Ready-Mix Concrete (RMC) Calculator: Delivery Volume in Yards
This ready-mix calculator converts your project dimensions into the cubic yards to order from a batch plant, plus a ballpark delivery cost. It also shows how your volume fits within a standard truckload so you can plan the pour.
Estimated concrete
Estimates only. Add ~5–10% for waste. Bag yields: 40 lb ≈ 0.30, 60 lb ≈ 0.45, 80 lb ≈ 0.60 cu ft. Concrete ≈ 150 lb per cu ft.
How to Use the Ready-Mix Concrete Calculator
- 1
Enter your dimensions
Type the length, width and thickness of your slab, footing or pad and choose your units, feet, inches or meters.
- 2
Get instant volume
See the result in cubic yards, cubic feet and cubic meters, plus weight, the moment you type, no page reloads.
- 3
Buy the right amount
We convert volume into the exact number of 40, 60 and 80 lb bags, truck loads and cost so you order without waste or shortfalls.
The formula
yd³ = (Length_ft × Width_ft × (Thickness_in ÷ 12) × qty) ÷ 27 × 1.10; truck loads = yd³ ÷ 10
- ·Length_ft = pour length (ft)
- ·Width_ft = pour width (ft)
- ·Thickness_in = slab thickness (in)
- ·1.10 = default 10% waste allowance
- ·10 = full drum capacity of one mixer truck (yd³)
Ready-mix is sold by the cubic yard, so convert cubic feet to yards and round up. A standard mixer carries about 10 yd³, so divide your total by 10 to see how many truck loads you need.
Worked examples
Example 1: Two-car driveway, 20 ft × 24 ft at 4 in
- Cubic feet = 20 × 24 × (4 ÷ 12) = 160 ft³
- Cubic yards = 160 ÷ 27 = 5.93 yd³
- Add 10% waste: 5.93 × 1.10 = 6.52 yd³
- Truck loads = 6.52 ÷ 10 = 0.65 → one truck
Result: About 6.5 yd³, delivered in a single truck
Example 2: Garage foundation slab, 30 ft × 40 ft at 6 in
- Cubic feet = 30 × 40 × (6 ÷ 12) = 600 ft³
- Cubic yards = 600 ÷ 27 = 22.22 yd³
- Add 10% waste: 22.22 × 1.10 = 24.44 yd³
- Truck loads = 24.44 ÷ 10 = 2.44 → 3 trucks
Result: About 24.5 yd³, needing three truck loads
Concrete calculators by project type
Concrete bag yield & coverage
How much mixed concrete a standard bag yields, and how far a cubic yard goes at common slab depths.
| Bag size | Yield (cu ft) | Bags per cubic yard |
|---|---|---|
| 40 lb | 0.30 | 90 |
| 60 lb | 0.45 | 60 |
| 80 lb | 0.60 | 45 |
- 40 lb
- 60 lb
- 80 lb
Related guides
Ready-Mix Concrete FAQs
How much does a yard of ready-mix concrete cost?
Ready-mix typically runs about $125 to $165 per cubic yard delivered, though prices vary by region, mix strength, and quantity ordered.
How many yards of concrete does a truck hold?
A standard fully loaded ready-mix truck carries about 10 cubic yards, though many deliveries run 8 to 10 yards depending on the truck.
Is there a short-load fee for small ready-mix orders?
Yes. Most suppliers charge a short-load or minimum-load fee when you order less than a full truck, often for anything under about 3 to 4 cubic yards.
How much extra ready-mix should I order?
Add roughly 5 to 10 percent to your calculated volume so you don't come up short from spillage or uneven subgrade, since a second delivery is costly.
What is RMC concrete?
RMC stands for ready-mix concrete, which is batched to a specified mix at a plant and delivered by truck ready to pour, rather than mixed on site from bags.
How long do I have to pour ready-mix after delivery?
Concrete should generally be placed within about 90 minutes of batching before it begins setting, so have your forms and crew ready before the truck arrives.
What is the difference between ready-mix and site-mixed concrete?
Ready-mix (RMC) is batched to spec at a plant and delivered wet in a rotating drum, so proportions and strength are controlled and consistent. Site-mixed concrete is combined by hand or in a small mixer on the job. Ready-mix is faster and more uniform for pours over about a cubic yard, while site-mixing suits small patch jobs.
How do I calculate how many yards of ready-mix to order?
Multiply length by width by thickness in feet to get cubic feet, divide by 27 to get cubic yards, then add roughly 10% for spillage and uneven subgrade. For example, a 160 ft³ slab is 5.93 yd³, or about 6.5 yd³ with waste. Always round up to the nearest quarter or half yard.
Can I order a partial yard of ready-mix?
Yes, most suppliers deliver in quarter-yard increments, but ordering less than a full truckload (about 10 yd³) often triggers a short-load fee. If you only need a yard or two, ask about the minimum charge before booking. Sometimes it is cheaper to order a bit extra than to pay two separate short-load fees.
What slump should I request for ready-mix concrete?
Slump measures workability; a 4-inch slump is typical for slabs and driveways, while footings can go slightly stiffer at 3 inches. Higher slump is easier to place but adding water on site weakens the mix. Tell the plant your application and they will batch the right slump rather than you thinning it in the truck.
Do I need to be ready before the truck arrives?
Yes. Forms, rebar, and subgrade should be fully set before the mixer shows up, and you need enough crew to place and finish within the delivery window. Most trucks allow about 5 to 10 minutes of unloading per yard before demurrage (waiting) charges start. Have your tools, screeds, and a wash-out spot ready in advance.
What happens if I order too little concrete?
Running short mid-pour forces a cold joint where fresh concrete meets partly set concrete, creating a weak seam. A second short-load delivery also costs another trip fee and delay. This is why the calculator adds a 10% waste margin; it is cheaper to have a little left over than to come up short.
How many wheelbarrows are in a yard of ready-mix?
A cubic yard is 27 cubic feet, and a typical contractor wheelbarrow holds about 3 cubic feet loaded safely. That works out to roughly 9 full wheelbarrows per yard. Budget extra crew and time if the truck cannot reach the forms and you must barrow the concrete by hand.