Concrete Footing Calculator Guide
Estimate concrete for continuous footings, deck post holes, and pier-style supports.
Continuous footings
For a rectangular footing, multiply length x width x depth, using feet for every dimension.
Round post holes
For round holes, use radius x radius x 3.14 x depth to estimate cubic feet.
Check local requirements
Footing size and depth can depend on frost line, soil, load, and local code.
Add waste
Post holes often use extra concrete because hole diameter and depth are rarely perfect.
FAQ
Can I size footings by calculator only?
No. Use local code or a professional for structural sizing.
Should post holes be below frost line?
In cold climates, many footings must extend below frost depth.
Do I need gravel under footings?
Some projects use gravel for drainage or leveling, but requirements vary.
Related guides
Next step
Open the calculators and enter your dimensions to estimate materials before you shop.