Estimate Bags, Volume & Cost for Slabs, Footings
Quickly calculate how much concrete you need for your project. Free, accurate, and easy to use for DIY and professionals.
Enter your project dimensions below to get an instant estimate of the concrete volume, number of bags needed, and total cost.
Advertisement
Our concrete calculator takes the guesswork out of your project planning. Whether you're pouring a small patio or a large foundation, getting the right amount of concrete is crucial to avoid costly mistakes.
The mathematical formula for calculating concrete volume for a rectangular area is straightforward: Volume (cubic feet) = Length (ft) × Width (ft) × Height/Depth (ft). Since concrete is typically sold by the cubic yard, we then convert: Volume (cubic yards) = Volume (cubic feet) ÷ 27.
Note: These are approximate values. Always check the manufacturer's instructions on the bag for exact coverage information.
Choose between rectangular slabs, footings, or circular projects based on your specific needs.
Input the length, width, and depth of your project area. Make sure to use consistent units.
Instantly see the concrete volume in cubic yards, number of bags needed, and estimated cost.
Let's say you're planning to pour a concrete slab for a garden shed that measures 10 feet by 10 feet with a standard 4-inch thickness:
Using our calculator, this entire process is automated, giving you accurate results in seconds.
For a standard 10x10 concrete slab with a 4-inch thickness, you'll need approximately 1.23 cubic yards of concrete. This equals about 56 bags of 60lb concrete mix. Always add 5-10% extra to account for spillage and uneven subgrade.
One cubic yard of concrete requires approximately 45 bags of 80lb concrete mix. Remember that yields can vary slightly between manufacturers, so it's always good to buy a few extra bags.
Cement is a binding powder that is never used alone—it's one component of concrete. Concrete is the finished product created when cement is mixed with aggregates like sand, gravel, and water. When you buy "concrete mix" in bags, you're getting the proper combination of these materials.
For small projects (under 1 cubic yard), bagged concrete is typically more cost-effective when you factor in delivery fees for ready-mix. For larger projects, ready-mix concrete delivered by truck is generally more economical. Our calculator helps you determine the exact amount needed for either approach.
For most residential applications like patios and walkways, 4 inches is standard. For driveways that will support vehicles, 5-6 inches is recommended. Heavier structures like garages may require 6+ inches. Always check local building codes for specific requirements.
Explore more construction and home improvement calculators
Calculate how much gravel you need for your driveway, pathway, or landscaping project.
Calculate mortar requirements for bricklaying, block work, and other masonry projects.
Convert measurements to cubic yards for various materials like soil, mulch, and concrete.