Concrete Footing Calculator (Continuous Wall Footings)
Volume for continuous trench/wall footings where width is in inches and length runs the full perimeter.
Formula
Cubic yards = Length(ft) × Width(in)/12 × Depth(in)/12 ÷ 27 × (1 + waste%).
Worked example
Inputs: Total footing length = 120 ft; Footing width = 16 in; Footing depth = 8 in; Waste allowance = 10 %; Bag yield = 0.6 cu ft/bag.
| Cubic yards | 4.35 |
|---|---|
| Cubic meters | 3.32 |
| Bags | 196 |
FAQ
What size should a footing be?
Footing size is set by your building code and engineer based on load and soil; this tool only computes volume.
Sources
- Geometry (volume/area formulas); no external constant needed
- QUIKRETE Concrete Mix (No. 1101) data sheet: 80 lb bag yields approx. 0.60 cu ft
Related
More Concrete calculators
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Last reviewed 2026-10-11.