Plan the Quantity, Mix, Trucks & Pour
Learn how to order ready-mix concrete without guessing. This step-by-step guide covers quantity, extra concrete, PSI and slump, delivery scheduling, truck spacing, pump coordination, site access, delivery tickets, water adjustments, short loads and the questions to ask your ready-mix supplier before pour day.
Calculate cubic yards from the actual forms and include a stated contingency for waste and irregularities.
Order the strength, slump, air and admixture requirements from the plans, specification or qualified professional.
Match truck spacing to the placement rate so the crew and concrete supply stay synchronized.
Confirm access, pump setup, crew, forms, reinforcement, washout and weather plan before dispatch.
Measure the actual forms, not just the drawing. Include thickened edges, footings, grade beams and irregular areas.
Allow for waste, over-excavation, uneven subgrade, form deflection and small measurement differences.
Have the project mix code or required PSI, slump, air and admixture requirements available.
Tell the supplier whether trucks discharge by chute, pump, conveyor, buggy or another method.
Reserve the delivery window and learn the supplier's confirmation, change and cancellation policy.
Estimate how many cubic yards per hour the crew can place so dispatch can plan the interval between loads.
Make sure trucks can enter, turn, discharge and leave safely and that the crew is ready before the first load arrives.
Verify the delivered mix and document any jobsite adjustments before concrete is placed.
Ready-mix concrete is normally ordered by volume—cubic yards in the United States or cubic meters in metric markets. For a rectangular slab, multiply length by width by thickness. If dimensions are in feet, thickness must also be converted to feet before calculating cubic feet. Divide cubic feet by 27 to get cubic yards.
For inches of thickness: Thickness(ft) = Thickness(in) ÷ 12.
Do not forget sections that are thicker than the nominal slab. Turn-down edges, grade beams, footings, post holes, steps, curbs and irregular excavations can add meaningful volume. Recheck the forms on site after excavation and before placing the order.
If you want a dedicated quantity tool, use the Concrete Slab Calculator, Square Concrete Calculator or Concrete Meter to Yard Calculator before calling the supplier.
One cubic yard contains 27 cubic feet. The square-foot coverage depends entirely on thickness. These are mathematical coverage values before waste, thickened edges or irregular subgrade.
| Thickness | Thickness in Feet | 1 yd³ Covers | Typical Planning Context |
|---|---|---|---|
| 3 in | 0.25 ft | 108 sq ft | Patios / light flatwork only where appropriate |
| 4 in | 0.333 ft | 81 sq ft | Common residential slab planning example |
| 5 in | 0.417 ft | 64.8 sq ft | Heavier flatwork where specified |
| 6 in | 0.50 ft | 54 sq ft | Driveways / structural flatwork where specified |
| 8 in | 0.667 ft | 40.5 sq ft | Thicker slabs and structural applications |
| 12 in | 1.00 ft | 27 sq ft | Footings / thick sections |
Ordering the exact theoretical volume leaves no room for field conditions. NRMCA CIP 8 identifies waste, over-excavation, spreading forms, irregular subgrade, settlement and other factors that can make the placed concrete appear short. Its guidance recommends estimating these contingencies and ordering roughly 4% to 10% more than the original volume calculation.
Consumer guidance sometimes recommends a larger 10%–15% cushion because homeowner measurements and subgrades can be less predictable. A repetitive commercial placement with well-controlled forms may need less contingency than a one-off backyard project with irregular excavation.
Example: 8.0 yd³ × 1.08 = 8.64 yd³ with an 8% allowance.
Round and order according to the producer's accepted increments. Ask whether partial-yard quantities are allowed and how the supplier handles final cleanup loads.
If the project has drawings or specifications, order the concrete required by those documents. The ready-mix supplier may identify the product by a mix code rather than by a long verbal description. For a small non-engineered project, explain the application and local exposure conditions to a qualified supplier or contractor, but do not guess at structural requirements.
Cemex's current direct-ordering workflow similarly asks customers to select the mix and choose from available slump and PSI strength options before scheduling delivery. That is a useful reminder that the product specification and delivery schedule are separate parts of the order.
Slump describes the consistency and workability of fresh concrete. A higher slump generally means the concrete is more fluid, but the correct slump should be achieved through the approved mix design and admixtures—not by casually adding excess water at the jobsite.
Tell the supplier the required slump from the mix design or project specification. If you are pumping concrete, tell both the ready-mix producer and pump company before the pour because pumpability can influence aggregate size, workability and mix selection.
Ready-mix trucks cannot always discharge directly into every form. The supplier should know whether you are using a standard rear-discharge chute, front-discharge truck, line pump, boom pump, conveyor, buggy or crane bucket. Placement method affects delivery timing and may affect the recommended mix.
If pumping, coordinate the pump and ready-mix schedules. The pump should be set up and ready before the first truck arrives. Confirm who supplies priming material, where trucks stage, how drivers will approach the hopper and where concrete washout will occur.
Concrete is a perishable product and ready-mix dispatch is a coordinated fleet operation. NRMCA's ordering checklist specifically calls out advance notice, will-call confirmation, add-on orders, change orders, cancellations, after-hours placements and weekend or holiday charges. Clarify those policies when placing the order—not after the first truck is already scheduled.
Give the supplier the exact project address and a reliable jobsite contact number. If GPS routing is misleading, provide gate, entrance or route instructions. Tell dispatch about road restrictions, narrow streets, steep grades or other access concerns.
NRMCA/ASCC's checklist asks for both truck spacing/duration and placement rate in cubic yards per hour. These are critical because too many trucks can create a queue of aging concrete, while too much spacing leaves the crew waiting and can create cold joints or finishing problems.
Estimate the crew's realistic production rate. A small hand-placed backyard slab may move much slower than a pump-fed commercial slab with a large crew. Do not schedule trucks based on the fastest five minutes of the job; use a sustainable placement rate.
Example: if a load is 9 yd³ and the crew can place 18 yd³/hour, the average interval is about 30 minutes. Actual dispatch must account for haul time and producer logistics.
A simple visual sequence from measurement to delivery. All labels remain contained inside the figure on desktop and mobile.
Use this checklist before calling dispatch. It follows the same categories emphasized in the NRMCA/ASCC ordering and scheduling checklist while keeping the language practical for homeowners, small contractors and project managers.
| Order Item | What to Have Ready | Why It Matters |
|---|---|---|
| Project & contact | Job name, address, purchaser, ordered-by contact, phone | Prevents dispatch confusion and gives driver a jobsite contact |
| Quantity | Total cubic yards plus planned contingency | Ready-mix is sold by fresh concrete volume |
| Date & start time | Requested delivery date, start time and confirmation policy | Coordinates plant, trucks and crew |
| Truck spacing | Minutes between trucks or desired cubic yards per hour | Matches supply to placement speed |
| Mix requirement | Mix code, PSI, slump, air, aggregate, admixtures or spec | Ensures the delivered product matches the project |
| Placement method | Chute, pump, conveyor, buggy or crane bucket | Affects workability and delivery coordination |
| Site access | Truck route, gate width, ground condition, washout location | Avoids unsafe or impossible access on pour day |
| Fees & policies | Short load, returned concrete, waiting, after-hours, weekend, cancellation | Prevents surprise charges |
Instead of starting with “How much is a truck of concrete?”, give dispatch the information needed to price and schedule the job correctly.
Example: “I need ready-mix for a residential slab at [job address]. My calculated quantity is 8.2 cubic yards and I am planning to order 8.8 yards including contingency. The project calls for [mix code / PSI], [slump], and [air requirement if applicable]. We are placing by [chute / pump] and expect to place about [X] yards per hour. I would like to start at [time] on [date]. Please tell me your minimum load, short-load policy, delivery charge, waiting-time policy, available truck spacing, cancellation deadline, and anything else you need from me.”
The order is not ready simply because the supplier has it in the dispatch system. Concrete delivery should not begin until the site and crew are ready to receive it.
Never direct a heavy concrete truck onto questionable soil, septic systems, underground utilities or unsupported pavement. The driver and supplier may refuse unsafe access, and that is preferable to damaging the site or creating a safety incident.
NRMCA quality guidance emphasizes that ready-mix delivered to a jobsite should be identifiable and traceable, and its ordering checklist is built around documenting the requested quantity, timing and mix details. Review the delivery ticket before discharge and compare it with the order.
Depending on the supplier and specification, the ticket may identify the plant, truck, quantity, batch time, mix code and material or admixture information. If testing is required, coordinate the testing agency so samples are taken correctly and without delaying placement.
Do not automatically add water just because concrete seems difficult to place. NRMCA's current concrete-materials FAQ explains that ASTM C94 allows jobsite water addition only when the slump is below what is required and the total mixing-water content allowed by the mix design is not exceeded. NRMCA also recommends documenting purchaser-requested additions on the delivery ticket.
NRMCA further notes that adjustments with water or admixtures should be followed by adequate mixing revolutions so the added material is incorporated uniformly. If you need more workability, discuss the acceptable adjustment with the producer rather than making an undocumented change.
NRMCA CIP 8 recommends reevaluating the volume needed toward the end of a placement and notifying the producer early enough to adjust the final two or three loads. This is much better than waiting until the crew discovers a shortage after the scheduled trucks are finished.
Track how much of the slab or forms have been filled compared with the volume delivered.
Tell the supplier whether the final load should be increased, reduced or cancelled according to policy.
Returned concrete has economic and environmental consequences, so do not wildly over-order just to feel safe.
“A concrete truck is 10 yards” is a common rule of thumb, but truck capacity and legal loading vary by equipment, producer and jurisdiction. NRMCA notes that producers generally load trucks at or near their rated mixer capacity, and central mixing equipment can also vary significantly in capacity.
For ordering purposes, you do not need to guess the truck size. Give dispatch the total quantity and placement rate; the producer will split the order into appropriate loads. Ask about the expected size of the first loads and final cleanup load if truck count matters for access, staging or pump scheduling.
Weather can affect placement rate, slump loss, setting time and finishing. Hot weather can shorten working time, while cold weather can require additional protection or different mix practices. Rain can disrupt site access, subgrade preparation and surface finishing.
Discuss hot- or cold-weather requirements with the supplier and contractor in advance. Do not wait for the first truck to ask whether a retarder, accelerator, chilled water or other adjustment should have been part of the mix design.
If the forecast makes the placement unsafe or likely to produce poor-quality work, follow the supplier and contractor's cancellation or rescheduling policy early enough to avoid unnecessary fees.
This guide is based on current industry guidance and practical supplier ordering workflows. For project specifications or contractual requirements, follow the applicable plans, standards and producer instructions.
Common questions about quantity, mix requirements, truck spacing, delivery tickets, water, short loads and pour-day coordination.