🏗️ Concrete Calculator

To calculate concrete volume, multiply length × width × thickness for rectangular slabs. For round slabs, use π × (diameter/2)² × thickness. Our calculator handles these formulas automatically and converts between units.

Standard concrete thickness varies by application: 4 inches for residential patios and walkways, 5-6 inches for driveways and garage floors, and 6-8 inches for commercial applications or heavy-duty use.

A cubic yard of concrete typically weighs about 4,000 pounds (2 tons). This can vary slightly depending on the mix design and aggregate types used in the concrete.

Each 80-pound bag yields approximately 0.6 cubic feet of concrete. For a 10×10×4 inch slab (33.3 cubic feet), you would need about 56 bags of 80-pound concrete mix.

For projects larger than 1 cubic yard, ready-mix concrete is typically more cost-effective and provides better quality. For smaller projects under 1 cubic yard, bagged concrete is more convenient and reduces waste.

It's recommended to order 5-10% extra concrete to account for spillage, uneven subgrade, and slight measurement variations. Our calculator includes a waste factor option for this purpose.

There are 27 cubic feet in 1 cubic yard. Concrete is typically sold by the cubic yard for ready-mix or by cubic feet for bagged concrete. Our calculator converts between both units automatically.

Concrete reaches about 70% of its strength in 7 days and over 90% in 28 days. However, you can typically walk on concrete after 24-48 hours and drive on it after 7 days, depending on conditions.