How Many Yards Does a Concrete Truck Hold? Why 10 Varies

A concrete truck mixer typically holds 8 to 12 cubic yards, according to the National Ready Mixed Concrete Association’s CIP 31, but 10 cubic yards is only a common planning figure; delivered load remains unguaranteed. The producer’s truck, concrete weight, axle configuration, and route restrictions determine what can legally reach your address; ask dispatch for the maximum delivered yards on your route.

Ten yards hardened into a “rule” because it sits inside that range and appears on producer charts. Repetition blurred rated mixer capacity, quantity batched, and route-permitted quantity. My old land-registry habit applies here: keep each label attached to what it describes.

How many cubic yards can a concrete truck actually deliver?

Mixer capacity and delivered load can differ by two cubic yards or more. NRMCA CIP 31 places truck mixers in an 8-to-12-cubic-yard range. Geiger Ready-Mix, one actual U.S. producer, publishes a truck-weight table that ends at 10 yards and 74,000 pounds. A 12-yard drum therefore does not promise a 12-yard delivery to your house.

Weight explains much of the gap. NRMCA CIP 36 gives normal-weight concrete a density range of 140 to 150 pounds per cubic foot. Since one cubic yard contains 27 cubic feet, the concrete alone weighs about 3,780 to 4,050 pounds per yard. Ten yards adds roughly 37,800 to 40,500 pounds before counting the chassis, drum, water, fuel, and driver.

The Federal Highway Administration’s Bridge Formula Weights states the Interstate limits: 80,000 pounds gross, 20,000 pounds on a single axle, and 34,000 pounds on a tandem, subject to stated exceptions. State rules, posted bridges, and local streets can lower the route limit. Ask dispatch, “How many yards will you load on the truck assigned to my address?”

How do you calculate cubic yards inside the actual forms?

Measure the formed space after excavation and compaction. Bowed forms, thickened edges, low subgrade, steps, piers, and blockouts change the plan volume.

1. Divide the pour into simple shapes. Record length and width in feet, then measure depth at several points rather than assuming every area is exactly 4 inches.
2. For each rectangular section, calculate length × width × thickness in inches ÷ 324. Add the sections and subtract true blockouts. Calculate thickened edges and footings separately.
3. Add a documented contingency. NRMCA CIP 8 recommends 4% to 10% over plan dimensions for waste, over-excavation, and similar variables. Give dispatch the measured quantity and the allowance as separate numbers.

A 24-by-24-foot slab at a true 4-inch depth contains 7.11 cubic yards: 24 × 24 × 4 ÷ 324. With NRMCA’s allowance, the order falls between 7.40 yards at 4% and 7.82 yards at 10%. The producer’s sales increment may move the final order to a quarter-yard or half-yard boundary.

One cubic yard covers exactly 81 square feet at 4 inches before waste. Accordingly, 8 yards covers 648 square feet, while 10 yards covers 810 square feet. Coverage shrinks fast when the base is low: NRMCA CIP 8 calculates that an extra 1/8 inch across a nominal 4-inch slab raises demand by about 3%.

What should you ask ready-mix dispatch before ordering?

Call with the site address, measured forms, plans or mix specification, placement method, and farthest distance from the truck position to the forms. Then ask these questions in plain language:

• “What is the maximum delivered load per truck on this route, and could a posted bridge or local road reduce it?”
• “At what quantity does your short-load or minimum-load fee begin, what increment do you sell, and what charges apply to waiting, a second call-back, returned concrete, cancellation, or weekend delivery?”
• “Which mix designation satisfies the project specification, exposure, strength, air, aggregate size, slump, fiber, color, and pumping requirements?” Let the designer, producer, and placer settle that answer.
• “What are the assigned truck’s width, height, gross loaded weight, discharge type, and chute reach? Will the driver inspect the proposed position before entering?”
• “How long is allowed for unloading, what truck interval matches my crew’s placement rate, and is the order confirmed or still on will-call?” Ozinga, for example, publishes a 60-minute unloading allowance per truck.
• “How much chute-washout liquid and solid material should I contain per truck, does the vehicle carry a washout system, and does a pump create a separate washout requirement?”

Minimums prove why local answers matter. Geiger says loads below 5 yards incur its minimum-load fee; Ozinga says loads below 7 yards may carry an additional delivery or minimum-load charge. Neither threshold is a national rule.

How does a transit mixer differ from a volumetric concrete truck?

| Question | Transit mixer | Volumetric mixer | | --- | --- | --- | | What travels to the house? | Fresh concrete in a rotating drum, mixed at the plant or in the truck | Cement, aggregate, water, and admixtures in separate compartments | | When is concrete produced? | The batch exists before placement | Ingredients are proportioned and mixed at the site as concrete is discharged | | Where does quantity flexibility come from? | Dispatch can adjust later loads, if the plant and schedule allow | Production can stop when the forms are full, within the unit’s carried-material limits | | Which standard applies? | ASTM C94/C94M, as cited by NRMCA CIP 31 | ASTM C685/C685M for volumetric batching and continuous mixing, as identified by the Volumetric Mixer Manufacturers Bureau |

For a measured residential slab, a transit mixer is familiar and often easier to source. Quote a volumetric truck when quantity is uncertain, the job is small, or several mixes are needed. Confirm calibration, production rate, billing, mix design, and ticketed output. “Mixed on site” leaves quality-control duties intact.

Which site problems can disrupt the planned load?

The first obstruction is sometimes the payload itself. NRMCA describes a loaded concrete truck as weighing about 80,000 pounds. Carroll’s Building Materials asks for stable access that can support that load, with a path at least 10 feet wide and 14 feet high, and warns against crossing curbs, sidewalks, or driveways. A residential driveway may look firm while its edge, culvert, pavers, or buried services remain vulnerable.

Chute reach is equally easy to overstate. Carroll’s gives approximately 12 feet from the back of its truck for the discharge chutes. Measure from a safe truck position, including the street setback and any fence, rather than from the nearest tire. Concrete also needs enough chute slope to flow; extra horizontal length on flat ground does not solve that geometry.

Soft soil, rain, uncompacted fill, septic components, branches, tight turns, parked cars, or a narrow gate can end the approach. Send dispatch photos and dimensions. The driver decides whether entering is safe.

Crew capacity completes the route from drum to form. Ozinga’s published 60-minute unload allowance means a 10-yard load would require an average placement rate of one yard every six minutes to empty within that window. Screeding and finishing continue after discharge. If the crew, buggies, vibrator, or pump cannot sustain the planned rate, order spacing and load size need to change.

What should you do if the truck cannot reach the forms?

Stop before the truck leaves the approved surface, then call dispatch. Establish the concrete’s batch time, condition, remaining unloading window, and the cost of waiting or return. Do not direct the driver over a curb, lawn, septic field, or questionable driveway to rescue the schedule.

Assess four routes with the dispatcher and placer:

| Option | When it may work | What must be confirmed | | --- | --- | --- | | Supplied chute arrangement | The form is close, downhill, and inside the producer’s stated reach | Approved chute count, support, slope, and a safe truck position | | Line or boom pump | The pour sits around a house, through a narrow opening, or beyond gravity reach | Pump availability, hose or boom reach, mix pumpability, priming, crew, and pump washout | | Buggy or wheelbarrow placement | The volume and travel path are genuinely manageable | Trips per yard, path capacity, backup equipment, extra labor, and continuous placement rate | | Return and reschedule | Safe placement cannot be organized while the concrete remains acceptable | Returned-concrete charge, cancellation terms, planned construction-joint location, and the next confirmed slot |

Water is no rescue plan. NRMCA CIP 31 says excessive jobsite water can cause segregation, delayed setting, cracking, and reduced strength and durability. Any water or admixture adjustment belongs under the producer’s procedure and must be written on the ticket.

How should you allow waste and space multiple loads?

Tie NRMCA’s 4%-to-10% allowance to site conditions. Accurate forms support the lower end; irregular excavation, thickened edges, and uncertain fill push upward. Plan where a small excess can go, or arrange a return under the producer’s policy. The EPA says unused wet concrete should not be dumped on bare ground.

For multiple trucks, divide by the delivered maximum that dispatch confirmed, then schedule to the crew’s measured discharge rate. If the crew empties 8 yards in 48 minutes, it is eight minutes slower than a plan based on five minutes per yard. Dispatch needs the real number.

No universal truck interval prevents a cold joint. NRMCA CIP 31 gives a broad two-to-eight-hour normal setting range; temperature, mix, wind, haul time, and subgrade alter behavior. Keep the receiving edge plastic and integrate loads while they can be consolidated. Have the contractor or designer identify a construction-joint location before the pour in case a truck fails or the gap becomes unworkable.

Near the end, measure the remaining forms and update dispatch. NRMCA CIP 8 specifically recommends reevaluating the final two or three loads so the producer can adjust them and avoid a small cleanup load.

How much concrete washout volume should you provide?

The EPA’s Concrete Washout best-management-practice sheet does not assign one gallon figure to every truck. It requires all washwater and solids to stay in a leakproof container, places the facility at least 50 feet from storm drains, open ditches, and waterbodies, and calls for service once the container exceeds 75% of capacity.

Ask dispatch for expected gallons per chute and whether washwater returns to the drum. Outpak’s published container capacities give real reference points: 50, 140, 260, and 605 gallons. Applying the EPA’s 75% threshold leaves 37.5, 105, 195, and 453.75 gallons respectively before service. Select a size that keeps all truck, pump, tool, and rain volume below that line; dispatch must supply the per-truck estimate. Mark the line where the crew can see it.

Which delivery-ticket and project notes should you keep?

The delivery ticket links a batch to a physical part of the home. Low sun is crossing my hands as I check the field list, and it catches the small entry most likely to be omitted from a casual photo: the truck number. I read these tickets as I once read unit schedules. A label becomes useful when it maps to an exact place.

Keep the original ticket and invoice with a sketch showing where each load went. Preserve the producer and plant, ticket and truck numbers, batch time, arrival, discharge start and finish, ordered and delivered yards, mix designation, specified strength, aggregate size, slump, air, fibers, color, and admixtures. Record every site-added water or admixture quantity and authorization.

Add weather, placement method, truck intervals, delays, returned quantity, washout disposition, test results, and dated photographs of subgrade, reinforcement, forms, joints, and the finished pour. NRMCA CIP 31 assigns the purchaser responsibility for checking and signing the ticket and recording special occurrences. Years later, that packet can distinguish similar-looking slabs before a repair, anchor, core, addition, or dispute reaches the wrong concrete.

Frequently asked questions

How many yards of concrete are needed for a 24-by-24-by-4-inch slab?

A 24-by-24-foot slab at 4 inches thick has a calculated volume of 7.11 cubic yards. NRMCA recommends adding 4% to 10% for waste, low spots, and dimensional variation, producing 7.40 to 7.82 yards. Confirm the forms’ actual depth and the producer’s ordering increment before rounding.

How much does 10 yards of concrete cost?

HomeAdvisor’s 2026 national estimate lists 10 cubic yards of concrete at $1,100 to $1,440. Treat that as a budgeting reference. A local delivered quote may add mix upgrades, fuel, environmental charges, tax, pumping, waiting time, or after-hours service; 10 yards usually avoids the short-load threshold.

How much does 20 yards of concrete cost?

HomeAdvisor’s 2026 national estimate places 20 cubic yards at $2,200 to $3,000 for the concrete. Delivery normally requires at least two trucks because NRMCA reports mixer capacities of 8 to 12 yards. Add any pump, delivery-zone, waiting-time, tax, and mix-design charges from the local written quote.

Is ready-mix concrete cheaper than bags?

Ready-mix is generally the practical cost choice for a multi-yard slab; bags can win for a tiny pour that would trigger a short-load charge. QUIKRETE’s data sheet gives an 80-pound bag an approximate 0.60-cubic-foot yield, so one cubic yard requires 45 bags and 7.11 yards requires about 320 bags.

What is a concrete mixer truck’s capacity in cubic meters?

NRMCA’s 8-to-12-cubic-yard mixer range converts to approximately 6.12 to 9.17 cubic meters. A common 10-yard load equals about 7.65 cubic meters, using the NIST conversion of one cubic yard to 0.7645549 cubic meter. Ask the producer for route-specific delivered capacity rather than relying on the drum range.

How many yards are needed for the planned pour?

Multiply each rectangular form’s length and width in feet by its thickness in inches, then divide by 324. Add separate footings and thickened edges, subtract blockouts, and total the sections. NRMCA recommends ordering 4% to 10% above plan volume for waste and field variation; confirm the final increment with dispatch.

Can the truck reach the forms without a pump?

Measure from a safe, load-bearing truck position to the farthest form. Carroll’s Building Materials publishes an approximate 12-foot chute reach for its trucks and requires 10-foot-wide, 14-foot-high stable access. Your supplier’s equipment may differ. Send photos and dimensions; use a pump when approved access and gravity reach do not meet.