Concrete calculators
Concrete Footing Calculator
Estimate concrete yards, bags, waste, and material-only cost for rectangular footings, grade beams, and trenches.
Footing dimensions
Estimate repeated rectangular footings or trenches.
This is for concrete material planning only, not structural design.
Estimated footing concrete
Live estimate for all repeated footings.
Recommended order
Includes 10% waste across all repeated footing runs.
Related
Related Calculators
Footing Planning Visual
Project visual
Footing volume starts with length, width, depth, and quantity
Use the calculator for material volume planning, but treat footing size, reinforcement, frost depth, soil conditions, and code approval as separate design decisions.
Footing Formula
Rectangular footing volume
Multiply length by width by depth, then multiply by quantity. Width and depth are entered in inches, so the calculator converts them to feet before estimating volume.
Structural planning note
Footing width, depth, reinforcement, and frost depth can depend on soil, loads, and local code. Use this page for material planning, not structural approval.
Common Footing Size Examples
| Use case | Common size | Note |
|---|---|---|
| Small wall or garden structure | 8-12 in wide x 8-12 in deep | Light-duty examples only; local requirements vary. |
| Deck or post footing trench | 12-16 in wide x 12 in deep | Depth may need to reach below frost line in some areas. |
| Foundation strip footing | 16-24 in wide x 8-12 in deep | Structural design should follow local code and load requirements. |
Concrete Footing Examples
30 ft footing, 12 x 12 inches
One 30 ft footing at 12 inches wide and 12 inches deep is about 1.11 cubic yards before waste.
Two 30 ft footings
Two repeated 30 ft footings at 12 x 12 inches need about 2.44 cubic yards with 10% waste.
20 ft footing, 16 x 12 inches
One 20 ft footing at 16 inches wide and 12 inches deep is about 0.99 cubic yards with 10% waste.
Concrete Footing Calculator FAQ
How do I calculate concrete for a footing?
Multiply footing length by width by depth. Convert inches to feet before multiplying, then divide cubic feet by 27 to get cubic yards.
How much concrete do I need for footings?
The amount depends on length, width, depth, quantity, and waste. This calculator totals repeated rectangular footings and converts the result to cubic yards.
What size should a concrete footing be?
Footing size depends on soil, loads, frost depth, structure type, and local code. Use this calculator for material planning, not structural design.
Should footing depth be entered in inches?
Yes. Enter width and depth in inches, while length is entered in feet. The calculator converts everything before estimating volume.
Should I add waste for footing concrete?
Yes. A 5-10% waste factor is commonly used for uneven trenches, spillage, and ordering margin.
Does this footing calculator include rebar?
No. It estimates concrete volume, bags, and material-only cost. Reinforcement requirements are separate.