Concrete Footing Calculator
Enter the total footing length, width and depth to get cubic yards of concrete for a trench or strip footing.
Enter your measurements to see what to buy.
How to calculate it
Enter the total footing length, width and depth to get cubic yards of concrete for a trench or strip footing.
Source: Volume = length × width × depth; 1 cubic yard = 27 cubic feet. Footing width and depth follow local building code.
A 60 ft footing, 18 in wide and 8 in deep: 60 × 1.5 × 0.667 = 60 ft³ ÷ 27 = 2.22 yd³. With 10% waste: 2.44 yd³.
Want the full step-by-step walkthrough? Read our How Many Bags of Concrete Do I Need?.
Purchasing & waste guidance
- Footing width and depth are set by local code — check before you dig.
- A typical residential wall footing is 16–24 in wide and at least 8 in thick.
- Add 10% waste for uneven trench bottoms and form leakage.
- Order ready-mix for anything over a yard; footings need to be poured in one continuous pass.
Assumptions & what’s included
- Footing is a continuous rectangular trench with uniform width and depth.
- Waste allowance covers uneven trench bottoms and form leakage.
- Price is per cubic yard of ready-mix and optional.
Frequently asked questions
How wide and deep should a concrete footing be?
Most residential footings are 16–24 in wide and at least 8 in thick, set by local code based on soil and load. Always confirm dimensions with your building department before pouring.
How much concrete do I need for a 50 ft footing?
A 50 ft footing, 20 in wide and 8 in deep needs about 2.06 yd³ before waste, or 2.27 yd³ with 10% added. The calculator handles any width and depth.
Can I pour a footing with bagged concrete?
Only for very short sections. Footings should be poured in one continuous pour, so ready-mix delivery is the practical choice for anything over a yard.
Related guides
Step-by-step project guides that use this calculator.