Concrete Footing Calculator
Updated Formulas shown
Continuous footings carry walls, garages and additions. Enter the total linear length of footing, its width and its depth. An 80 ft run of 16 × 8 in footing needs about 2.9 yd³ with 10% waste.
Concrete for footing
2.9 yd³
Over ~1 yd³, ready-mix delivery is usually cheaper than bags.
- 80 lb bags
- 1310.6 ft³ each
- 80 lb bags
- 131
- 60 lb bags
- 174
- Cubic feet
- 78.22 ft³
- Cubic meters
- 2.22 m³
- Weight (wet)
- 11,733 lb
Includes your waste allowance. Bag yields: 40 lb = 0.30 ft³, 60 lb = 0.45 ft³, 80 lb = 0.60 ft³.
The formula
Volume = length (ft) × width (in ÷ 12) × depth (in ÷ 12). Divide by 27 for cubic yards.
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Frequently asked questions
How wide should a footing be?
A common rule is twice the wall thickness — 16 in for an 8 in wall — but local code and soil bearing capacity govern. Check your permit drawings.
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Estimates only. Check quantities with your supplier or contractor before ordering.