Concrete Volume Calculator
Whether you're pouring a slab or filling a round column, this calculator handles both rectangular and circular shapes to give you exact cubic yards and total weight.
Rectangular vs. Circular Concrete Calculations
Rectangular pours are the most common. You multiply length times width to get area, then multiply by depth to get volume. Remember to convert depth from inches to feet by dividing by 12, since length and width are already in feet.
Circular pours use the formula for cylinder volume: Ο Γ radiusΒ² Γ height. The radius is half the diameter. If your column is 12 inches across and 4 feet tall, the radius is 6 inches or 0.5 feet, giving Ο Γ 0.25 Γ 4 = 3.14 cubic feet.
Most construction involves a mix of shapes. A typical foundation might have rectangular footings plus circular pier holes. Calculate each element separately, then add the volumes to get your total concrete order.
Why Concrete Weight Matters
Concrete is heavy. A single cubic yard tips the scales at over 4,000 pounds, meaning a modest 5-yard pour weighs more than 10 tons. That weight drives decisions about equipment, access, and scheduling.
Wheelbarrows max out around 6 cubic feet per load, and even strong workers struggle to push that much wet concrete up a slope. Pumps and conveyors become essential for large pours or hard-to-reach areas.
Weight also affects formwork. Forms must withstand the hydrostatic pressure of wet concrete pushing outward. Taller pours create more pressure at the base, requiring stronger bracing and tie systems to prevent blowouts.
Ordering the Right Amount of Concrete
Concrete suppliers round up to the nearest quarter or half yard. If your calculation shows 3.2 yards, order 3.5. Running short means an emergency call for more concrete, rushed finishing work, and a cold joint that weakens the slab.
Add 5 to 10 percent for waste. Over-excavation, uneven subgrade, and spillage during the pour all consume extra concrete. Forms are never perfectly straight, and stakes compress the ground beneath them.
Plan your pour for a time when the truck can get close. Pump trucks charge extra and may not fit on narrow residential lots. If the driver has to chute concrete more than 12 feet, expect delays and potential segregation of the mix.
Frequently Asked Questions
How much does a cubic yard of concrete weigh?
Standard concrete weighs about 4,050 pounds per cubic yard when fully cured. Lightweight mixes weigh 3,000 to 3,500 pounds per yard.
Do I calculate depth in inches or feet?
This calculator accepts depth in inches for convenience, since most concrete pours are measured in inches. Length and width stay in feet.
Can I use this for irregular shapes?
For complex shapes, break the area into rectangles or circles and calculate each section separately, then add the results together.
What about concrete for stairs or slopes?
Sloped pours require volume calculations based on the average thickness. Stairs work best when calculated as a series of rectangular blocks.
Why does the calculator show weight?
Weight helps you plan equipment needs. A full cubic yard weighs over two tons, so you need proper wheelbarrows, mixing equipment, and potentially a truck or trailer for transport.