How much concrete for a footing?
A footing estimate uses total run length, footing width, and footing depth. Convert width and depth into feet, multiply the dimensions, divide by 27, then add waste. For example, a 40 ft run that is 16 inches wide and 8 inches deep is about 1.32 cubic yards before waste, or about 1.45 cubic yards with 10% waste.
Common footing dimensions for planning
Common residential planning examples include 12 in wide x 6 in deep for light frame walls, 16 in wide x 8 in deep for many 8 in block wall examples, and 20 in wide x 10 in deep for heavier wall examples. These are quantity examples only. Required footing size, frost depth, reinforcement, and bearing details must come from local code, plans, soil conditions, or qualified guidance.
Concrete footing calculation example
For a 30 x 40 ft house foundation perimeter, the total run is 140 linear feet. Using a 16 in wide x 8 in deep footing with 10% waste: cubic yards = (140 x 1.33 x 0.67) / 27 x 1.10, which is about 5.07 cubic yards. A ready-mix order might be discussed around 5.25 cubic yards depending on supplier rounding.
Concrete footing cost per linear foot
Using a broad ready-mix material reference of $125-$165 per cubic yard, concrete material for a 16 in x 8 in footing is about $4.10-$5.45 per linear foot before waste. A 12 in x 6 in footing is about $2.30-$3.05 per linear foot, while a 24 in x 12 in footing is about $9.25-$12.25 per linear foot before waste. Labor, forms, excavation, rebar, inspection, delivery fees, and local pricing are separate.
Common concrete slab sizes
Cubic yards below are before waste. Add your project waste percentage before ordering.
| Slab size | 4 in thick | 5 in thick | 6 in thick |
|---|---|---|---|
| 10 ft x 10 ft | 1.23 cu yd | 1.54 cu yd | 1.85 cu yd |
| 10 ft x 12 ft | 1.48 cu yd | 1.85 cu yd | 2.22 cu yd |
| 12 ft x 12 ft | 1.78 cu yd | 2.22 cu yd | 2.67 cu yd |
| 20 ft x 20 ft | 4.94 cu yd | 6.17 cu yd | 7.41 cu yd |
| 24 ft x 24 ft | 7.11 cu yd | 8.89 cu yd | 10.67 cu yd |
| 30 ft x 40 ft | 14.81 cu yd | 18.52 cu yd | 22.22 cu yd |
Before you calculate
- Measure the formed dimensions, not just the finished visible surface.
- Break complex foundations into separate rectangular sections.
- Use thickness in inches and keep waste visible for excavation and form variation.
Common mistakes
- Missing thickened edges, grade beams, steps, or separate footing runs.
- Using plan dimensions without checking actual forms.
- Treating a material calculator as structural design.
Formula
cubic yards = (length * width * (thickness / 12) / 27) * (1 + wastePercent / 100)
Assumptions
- Defaults represent a a grade beam concrete estimate quantity example.
- Width is entered in feet and depth uses the thickness input in inches.
- Required footing size, frost depth, reinforcement, and inspection details must come from project requirements.
Example
Estimated concrete needed (cubic yards): 2.44 cubic yards
How to use this calculator
- Enter length in ft.
- Enter width in ft.
- Enter thickness in in.
- Enter waste in %.
- Review the live estimate and compare it with the example result.
- Check the formula, assumptions, product labels, and site conditions before using the Grade Beam Concrete Calculator result to plan materials.
Before you buy materials
- Confirm dimensions, reinforcement, and inspection requirements before ordering concrete.
- Use the estimate as a quantity planning number for supplier conversations.
FAQ
What is the example grade beam concrete cubic-yard result?
Use length, width, thickness or depth, and waste, then calculate the planning result. In the default example, the result is 2.44 cubic yards.
How deep should a concrete footing be?
Footing depth depends on local frost depth, soil, load, and building requirements. As a planning reference, warm-climate footings can be much shallower than cold-climate footings, where frost depth may be several feet. Verify the required depth with local code, permit drawings, or a qualified professional before pouring.
How wide should a concrete footing be?
A common planning rule is that a footing is often wider than the wall it supports. For example, a quantity estimate might use a 16 inch wide footing under an 8 inch block wall. Final width depends on load, soil bearing, wall type, and local requirements.
How much concrete do I need for a house foundation footing?
For a simple example, a 30 x 40 ft foundation perimeter is 140 linear feet. At 16 inches wide and 8 inches deep, it needs about 4.61 cubic yards before waste, or about 5.07 cubic yards with 10% waste.
What PSI concrete should I use for footings?
Concrete strength should follow the project plans and local requirements. Broad residential planning references often discuss mixes around 3,000-4,000 PSI, but this calculator does not choose a structural mix design.
How do I calculate concrete for a footing?
Use cubic yards = length x width x depth in feet / 27, then add waste if needed. Example: 40 ft x 1.33 ft x 0.67 ft / 27 x 1.10 = about 1.45 cubic yards.
Should I calculate each footing section separately?
Yes. Calculate each straight run, corner pad, stepped section, or thickened area separately when dimensions change, then add the cubic yards together for the total order.
Related calculators
This calculator is for planning estimates only. Verify final quantities with product labels, project conditions, and a qualified professional when accuracy matters.