Use the dimensions specified for the project. This calculator does not size a footing or determine soil capacity, reinforcement, frost depth, or structural suitability.
01 / Formula
How this is calculated
Cubic feet = length ft × (width in ÷ 12) × (depth in ÷ 12) × quantity02 / Assumptions
What the estimate assumes
- ✓Each footing is a uniform rectangular prism.
- ✓Dimensions come from an approved design or qualified source.
- ✓Keyways, piers, steps, and grade beams are calculated separately.
03 / Worked example
See the math in context
Forty linear feet of footing 16 inches wide and 8 inches deep contains 35.56 cubic feet, or 1.32 cubic yards before waste.
04 / Guidance
Quantity is not design
Footing dimensions depend on loads, soil, climate, structure, and applicable requirements. Use this tool only after those dimensions are established.
Questions
Frequently asked
Should I order exactly the calculated amount?+
Usually no. Excavation variation, form dimensions, spillage, and uneven subgrade can increase actual volume. Use the editable waste allowance and discuss minimum loads and order increments with the supplier.
How many cubic feet are in a cubic yard?+
There are exactly 27 cubic feet in one cubic yard. Divide cubic feet by 27 to convert to cubic yards.
Does this replace a structural design?+
No. These tools estimate material quantity only. A qualified professional and applicable plans, codes, site conditions, reinforcement requirements, and manufacturer instructions govern the project.
Sources