Concrete
Continuous Footing Concrete Calculator
Continuous footings run under foundation walls. Enter the total footing length around the building plus the footing width and depth to get the concrete volume.
Formula
Volume (ft³) = length (ft) × width (in) ÷ 12 × depth (in) ÷ 12. Cubic yards = ft³ ÷ 27, then multiply by (1 + waste%).
Worked example
A 120 ft perimeter footing, 20 in wide and 10 in deep: 120 × 1.667 × 0.833 = 166.67 ft³ = 6.17 yd³. With 10% waste: 6.79 yd³.
Assumptions and limits
- Uniform rectangular cross-section; stepped footings need each segment calculated separately.
- Trench-poured footings often run wider than the design width; increase waste accordingly.
- For estimation only. A licensed Professional Engineer (PE) must design and stamp any structural, foundation or life-safety element.
Frequently asked questions
How wide should a house footing be?
The IRC (Table R403.1(1)) sets minimum footing widths based on the number of stories, construction type and the soil's allowable bearing pressure. Many one-story homes on average soils fall in the 12 to 20 in range, but your plans govern.
How thick is a typical residential footing?
The IRC requires a minimum footing thickness of 6 in. Many homes use 8 to 12 in.
Do corners count twice when measuring length?
If you add the outside dimensions of every wall, the corners are double counted. Use the footing centerline length for an accurate total.