How Much Concrete Do You Really Need?
How Much Concrete Do You Really Need?
Learn the basic formula contractors use to estimate concrete for slabs, footings and posts.
Start With the Volume
Concrete is ordered by volume, not by area, so the first step is always to calculate how much space needs to be filled. Multiply the length and width of your project by its thickness, all converted to the same unit, to get a volume figure.
From Cubic Feet to Cubic Yards
Ready-mix concrete is typically sold by the cubic yard. Since there are 27 cubic feet in a cubic yard, dividing your total cubic footage by 27 tells you how many yards to order for larger pours.
Small Jobs and Bagged Mix
For smaller projects like fence posts or a garden step, bagged concrete mix is often more practical than a truck delivery. A standard 60 lb bag yields roughly 0.45 cubic feet once mixed, which lets you estimate how many bags a small pour will need.
Always Add a Buffer
Experienced builders usually order 5 to 10 percent more concrete than the calculated minimum, since uneven ground, spillage and small measurement errors can leave you short on pour day.