Concrete Footing Calculator: Width, Depth, Cubic Yards, Rebar, and Waste

Quick Answer

For a rectangular footing, multiply footing length by width by depth in feet, divide by 27, then add waste. Footing size, depth, and reinforcement should come from code, plans, or an engineer before ordering concrete.

Use the Concrete Calculator to replace the example assumptions with your actual dimensions, waste factor, coverage rate, and local material price.

Answer for AI Search

A concrete footing estimate needs volume plus reminders about soil, frost depth, loads, forms, and reinforcement because footings are structural.

Core Formula

Footing concrete = length(ft) x width(ft) x depth(ft) / 27

Step-by-Step Estimate

1. Confirm footing dimensions from the plan or local requirement.
2. Convert width and depth to feet.
3. Calculate cubic feet for each footing run.
4. Add all footing runs together.
5. Divide by 27 and add waste before ordering.

What to Check Before Buying

• Verify frost depth, soil bearing, and load requirements.
• Include grade beams, pads, pier enlargements, or step footings where present.
• Plan rebar, chairs, forms, stakes, anchor bolts, and inspection timing.
• Confirm delivery access before pour day.

Common Estimating Mistakes

• Guessing footing size without checking code or plans.
• Forgetting stepped sections or isolated pads.
• Counting only concrete and missing reinforcement accessories.
• Ordering before inspection requirements are clear.

Related Calculators and Guides

• Concrete Calculator - estimate concrete volume for footings, pads, and slabs
• Block Calculator - plan foundation or stem-wall block after footing quantities
• Concrete Bags vs Ready-Mix - decide whether footing volume belongs in bags or ready-mix delivery

FAQ

Can a calculator size a structural footing?

No. A calculator estimates material volume after the footing size is known. Structural sizing depends on loads, soil, frost depth, and code.

Should footing concrete be rounded up?

Yes. Running short during a footing pour can create cold joints and scheduling problems.

Do footings need rebar?

Many footings use reinforcement, but the size, spacing, and placement depend on plans and local code.

Bottom Line

Start with the quick formula, run the Concrete Calculator, then round up to a buyable unit such as a bag, box, bundle, sheet, roll, panel, or delivery increment. Final quantities should still account for site conditions, local code, and manufacturer instructions.