Concrete Foundation Calculator — Concrete-Depot.com

Calculate concrete needed for footings and foundations. Get results in cubic yards, bags, and more.

Foundation Type Select the shape of your foundation

Length

Total length of footing Please enter a valid length

Width

Footing width (typically 16-20 inches) Please enter a valid width

Diameter

Diameter of circular footing Please enter a valid diameter

Depth

Depth below grade Please enter a valid depth

Quantity Number of footings

Add 10% waste buffer

3D Foundation Preview

Total Concrete Needed –

In cubic meters –

In cubic feet –

60 lb bags –

80 lb bags –

With 10% waste –

Total for 1 footings –

Additional Information

How to Use

Step 1: Select your foundation type from the dropdown (Rectangular, Circular, Strip, or Pad footing).

Step 2: Enter the dimensions of your foundation. The calculator accepts feet, inches, meters, or centimeters.

Step 3: Specify the depth of your footing below grade level.

Step 4: Enter the quantity if you're calculating for multiple footings.

Step 5: Check the waste buffer option to add 10% extra for spillage and over-excavation.

Step 6: Results update automatically as you type. Download the PDF report for your records.

Formula Used

Rectangular/Strip/Pad Footing:

Volume = Length × Width × Depth
Volume (cu yd) = (L(ft) × W(ft) × D(ft)) ÷ 27

Circular Footing:

Volume = π × r² × Depth
Volume (cu yd) = (π × (Diameter/2)² × Depth) ÷ 27

Bag Calculations:

60 lb bags = Total cu ft ÷ 0.45
80 lb bags = Total cu ft ÷ 0.60

Foundation Design Tips

Standard footing widths: 16-20 inches for residential foundations, 24+ inches for commercial
Depth requirements: Typically 12-24 inches below grade, or below frost line in cold climates
Soil bearing capacity: Sandy soil: 2,000-3,000 psf | Clay soil: 1,500-3,000 psf | Rock: 4,000+ psf
Rebar spacing: Use #4 rebar at 12-18 inches on center for most footings
Concrete strength: 2,500-3,000 PSI for residential, 3,500-4,000 PSI for commercial
Frost depth: Check local building codes - typically 12-48 inches depending on climate zone

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