Concrete Cubic Yards Calculator

Cubic yards is the standard unit of measurement used by ready-mix concrete suppliers in the United States. One cubic yard is equal to 27 cubic feet. Ready-mix trucks typically hold between 8 and 10 cubic yards of wet concrete. When planning large foundation pours, driveways, or commercial slabs, calculating in cubic yards is essential for ordering the correct truck capacities.

Short-load fees are charged for orders below 3 to 5 cubic yards, making bags more cost-effective for very small jobs. Always add a 5% to 10% waste allowance to cover form expansion, soil unevenness, and spillage.

If the truck cannot access the pour location directly, you must arrange for a concrete pump or multiple wheelbarrows, which requires additional labor. Be ready for the pour before the truck arrives: ready-mix plants charge demurrage fees if the truck sits idle on site for more than 45 to 60 minutes.

Ready-Mix Truck Access & Site Setup

A fully loaded concrete mixer truck weighs up to 70,000 pounds (35 short tons) and requires a clearance width of 10 feet and height of 13.5 feet. Before ordering a bulk delivery, verify that your driveway or access path can support this weight without cracking underground sewer lines or water mains. The truck's discharge chutes can reach up to 12 to 18 feet from the back of the truck. If the pour site is further away, you must set up a concrete pump, hire wheelbarrow operators, or use a motorized buggy to transport the wet concrete.

When placing ready-mix orders exceeding 10 cubic yards, organizing a team of at least three experienced workers handles the rapid discharge rate safely. Having rakes, floats, and vibrators staged before the truck backs in ensures placement within transit time guidelines.

Demurrage & Standby Time Charges

Concrete suppliers charge standby fees, often called demurrage, if their truck is kept on site for too long. Standard ready-mix delivery agreements allow for 45 to 60 minutes of free unloading time. Once this window closes, fees accrue at a rate of $2 to $5 per minute. Staging your discharge chutes, placing wooden ramps, and organizing your work crew before the transit mixer backs up ensures a fast pour and avoids expensive demurrage charges.

Additionally, ready-mix concrete plant dispatchers appreciate receiving delivery orders at least 48 hours in advance, especially during the peak summer construction season. Clearly stating your structural slab placement rate and specifying any required chemical retarder or accelerator additives ensures your batch flows at the correct speed on arrival.

Example 1 — US Standard (Imperial):
Pouring a foundation slab 45 ft long × 30 ft wide × 6 inches thick (0.5 ft) with a 10% waste margin:
• Net Volume = 45 ft × 30 ft × 0.5 ft = 675.0 cubic feet.
• Cubic Yards = 675.0 ÷ 27 = 25.0 cubic yards.
• Total with 10% Waste = 25.0 × 1.10 = 27.50 cubic yards.

Example 2 — GCC/Metric Standard:
Converting 20.0 cubic meters of concrete to cubic yards for a global project baseline:
• Net Volume = 20.0 cubic meters.
• Cubic Yards = 20.0 × 1.308 = 26.16 cubic yards.