Free Tool
Concrete Volume Calculator
Calculate how many cubic yards of concrete you need for slabs, footings, walls, and columns. Add a waste factor to make sure you order enough.
Industry standard: 5-10% for slabs, 10-15% for complex forms
Volume (exact)
0
cubic yards
Order Amount
0
cubic yards (with waste)
Volume
0
cubic feet
Weight (est.)
0
pounds
How to Calculate Concrete Volume
The basic formula for a rectangular slab is straightforward:
Volume (cubic yards) = (Length × Width × Thickness) ÷ 27
Where length and width are in feet, and thickness is converted to feet (inches ÷ 12)
For round columns or piers, the formula uses the radius:
Volume = π × r² × height ÷ 46,656 × quantity
Where r = radius in inches, height in inches, result in cubic yards
Why Add a Waste Factor?
You should always order more concrete than the exact calculated volume. Concrete is wasted through:
- Uneven subgrade — ground is never perfectly flat, so some areas will be thicker
- Form deflection — forms can bow slightly under the weight of wet concrete
- Spillage — some concrete is lost during pouring and finishing
- Over-excavation — footings dug slightly wider or deeper than planned
A 10% waste factor is standard for most slab work. Use 15% for irregular shapes or complex forms. Running short mid-pour is far more expensive than ordering an extra half yard.
Common Slab Thicknesses
| Application | Typical Thickness |
|---|---|
| Sidewalks and patios | 4 inches |
| Residential garage floors | 4–6 inches |
| Residential slab-on-grade | 4–6 inches |
| Driveways (residential) | 4–6 inches |
| Commercial slabs | 6–8 inches |
| Monolithic slab thickened edges | 12–24 inches |
Track concrete costs across every pour
ConstructiveCore lets you estimate, order, and track material costs by job — so you always know where your budget stands.