Concrete Footing Calculator
Estimate concrete volume for one or more strip footings from length, width and depth.
Project details
Enter your measurements below.
Count the concrete after the footing dimensions are already known
A footing calculator should not design a footing. Its job is much narrower: once the required width, depth and length have been established for the project, it can turn those dimensions into a concrete volume for ordering. This is useful for continuous strip footings and repeated rectangular footing runs. Measure the actual excavation or form dimensions and keep separate footing types in separate calculations. Soil capacity, reinforcement, frost depth, bearing, loads and code requirements are outside this quantity estimate.
Converts known footing dimensions into concrete volume.
It does not choose footing width, depth, reinforcement or bearing design.
Combine identical runs by quantity; calculate different footing sizes separately.
How to use the Concrete Footing Calculator
- Use footing dimensions from the applicable project design or requirement rather than selecting dimensions from the calculator.
- Measure or enter the total footing length, width and concrete depth in consistent units.
- Multiply length × width × depth for each footing type, then multiply by the number of identical runs if needed.
- Convert the combined volume to the supplier's ordering unit and review excavation/form conditions before finalizing the quantity.
Quantity follows the design
The formula is simple because the structural decisions should already have been made elsewhere. DIYGauge deliberately does not infer safe footing dimensions from building size or soil conditions.
Use the volume for concrete planning
Once the geometry is confirmed, use the result to discuss concrete supply, access and placement. Keep reinforcing steel, formwork and excavation quantities separate.
Worked example: one continuous strip footing
- Length
- 36 ft
- Width
- 20 in = 1.667 ft
- Depth
- 10 in = 0.833 ft
- Volume
- ≈ 50.0 cu ft
36 × 1.667 × 0.833 is about 50 cubic feet, or roughly 1.85 cubic yards before any project-specific ordering allowance. That result assumes the entered footing dimensions are already appropriate for the project.
Practical planning tips
If the trench sides are rough or wider than the design, estimate the actual placed concrete volume rather than pretending the excavation is perfectly rectangular.
Calculate step footings or sections with different depths separately and add the volumes.
Keep form dimensions and excavation dimensions distinct when forms will control the concrete size.
Coordinate the quantity with access and pour sequence; the calculator does not account for pump lines, leftover concrete or batching minimums.
Common mistakes to avoid
Using the calculator to choose a footing size instead of calculating a size already established by the design.
Mixing inches and feet within the volume formula.
Averaging several very different footing depths into one number without checking the resulting volume.
Including excavation overcut automatically as structural footing volume when forms will actually limit the concrete.
Concrete Footing Calculator FAQs
Does this calculator tell me how wide a footing should be?+
No. Width, depth, reinforcement and bearing requirements depend on loads, soil, structure and applicable design/code. Enter dimensions that have already been established.
Can I calculate several footings at once?+
Yes when they have the same dimensions. For different footing types, calculate each group separately and add the concrete volumes.
Should I use trench dimensions or form dimensions?+
Use the dimensions that will actually control the placed concrete. If concrete is poured directly against excavation, irregular trench size can affect volume.
Does the result include rebar?+
No. This is concrete volume only. Reinforcement and formwork need separate project quantities.