Concrete Footing Calculator
A concrete footing calculator finds the volume of a footing trench by multiplying its length by width by depth, then converting to cubic yards. Footings are long and narrow, so this is the right tool when you are pouring the base that supports a foundation, wall or post. Enter your footing dimensions below.
For multiple identical footings, a count multiplier is available.
- 80 lb bags
- 0
- Estimated cost
- $0.00
Enter your dimensions to see the result.
Estimate only. Material yields and prices vary by supplier and region; confirm before ordering.
How Do You Calculate Concrete for Footings?
To calculate concrete for a footing, multiply the trench length by its width by its depth, all in feet, then divide by 27 for cubic yards. A footing 20 feet long, 16 inches wide and 8 inches deep works out to 20 times 1.33 times 0.667, about 17.8 cubic feet, or 0.66 cubic yards. For several identical footings, calculate one and multiply by the count, which the calculator handles with its quantity field.
What Size Are Typical Footings?
Footing dimensions follow the load and local code. Residential footings are often 16 to 24 inches wide and 8 to 12 inches deep, but the right size depends on soil and structure, so check your plans or local building code. Because footings are continuous and carry the structure, getting the volume right matters: under-ordering means a cold joint in a load-bearing element. The calculator lets you match the exact spec.
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Frequently asked questions
- How do I calculate concrete for footings?
- Multiply footing length by width by depth in feet, then divide by 27 for cubic yards. For multiple footings, multiply by the number of them. The calculator includes a count field.
- How much concrete for a 20 foot footing?
- A 20 foot footing at 16 inches wide and 8 inches deep needs about 0.66 cubic yards. Wider or deeper footings raise this quickly, so use the exact dimensions.