Concrete Footing Calculator
Cubic yards and bags for a strip or continuous footing — length, width and depth.
Concrete footing calculator
Shape
Waste factor
Concrete needed (waste in)
5.43 yd³
146.7 ft³ · 4.15 m³
Bags (rounded up)
245
80 lb
326
60 lb
392
50 lb
489
40 lb
- Ready-mix (delivered)
- $739 – $1,207
- Bagged (80 lb)
- $1,348 – $2,205
- Installed (slab)
- $2,200 – $4,800
Concrete 5.43 yd³
Sizing a footing
A footing spreads a wall or column load into the soil, so it runs a length at a set width and depth. Multiply the three (in consistent units) for the volume. Footings must reach below the frost line — confirm depth and width against your local code and soil.
Prices updated January 2026 National US averages · reviewed quarterly
Volumes use standard bag yields and a 10% waste allowance; costs are national US averages that vary by region, mix and finish. See our methodology for exactly how each figure is worked out, or check the reference sources:
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Frequently asked questions
How much concrete for a footing?
Footing volume is length × width × depth. A 20 ft footing 16" wide and 8" deep needs about 0.66 cubic yards. Enter your dimensions above for the exact yards and bag count.
How deep should a footing be?
Footings must sit below the frost line and be sized to the load — commonly 8–12" deep and at least twice the wall thickness wide. Check your local code.
What bag size for footings?
For anything beyond a couple of footings, ready-mix is easier. For small jobs, 60 or 80 lb bags are common — the calculator shows every size.