Concrete Footing Calculator

Q: How much concrete do I need for a footing?

Multiply length × width × depth in feet, divide by 27 for cubic yards, then add waste.

Q: How deep should footings be?

Footings should extend below local frost depth. Typical depths vary by climate and code.

Q: How much does a concrete footing cost?

Total cost depends on volume, mix price, labor, and site conditions. Use local quotes for accurate budgeting.

A concrete footing calculator estimates the volume of concrete needed for foundation footings that spread structural loads to soil. Calculate cubic yards, cubic feet, and 80-lb bags for rectangular strip footings (under walls), pad footings (isolated columns), and pier footings (cylindrical Sonotube forms). Enter dimensions below to get accurate material estimates with a built-in waste factor.

Inputs

Footing Type

Length (ft)

Width (in)

Depth (in)

Built-in waste factor: 10%.

Quick Reference: Typical Footing Sizes

Use Case	Typical Width / Diameter	Typical Depth
Fence posts	8-10 in dia	24-36 in
Deck posts	10-12 in dia	36-48 in
Small shed slab edge	12-16 in wide	12-18 in
1-story wall footing	12-16 in wide	12-24 in
2-story wall footing	16-24 in wide	18-30 in

Verify final footing dimensions with local code requirements and, when needed, a licensed engineer.

Results

Concrete volume

0.54 yd³

14.67 ft³ • 0.42 m³

80-lb bags (rough)

24.44

Assumes ~0.6 ft³ yield per 80-lb bag (varies by mix).

Estimated cost

$67.9 - $81.48

(Typical pricing — varies by region)

Want a full breakdown of delivery fees, short loads, PSI pricing, and what affects ready-mix rates? See our pricing breakdown.

Assumptions

Rectangular mode uses strip/pad footing volume from length × width × depth.
Pier mode uses cylindrical volume from diameter, depth, and number of piers.
A fixed 10% waste factor is already included.
Bag yield is an approximation; check your product label.

Next Steps: Concrete Project Workflow

Example

A 10 ft footing at 16 inches wide and 12 inches deep needs about 0.54 yd³ of concrete with waste. For Sonotube piers, switch to Pier mode and enter diameter, depth, and pier count.

Footing Size & Depth Guidelines

Minimum depth: 12 inches or below frost line (whichever is deeper).

Typical depths: warm climates 12-18 inches, moderate climates 24-36 inches, cold climates 42-48 inches.
Common residential footing widths: 12-16 inches for 1-story wood frame and 16-24 inches for 2-story structures.
Wider footings required for poor soil conditions.
Deck and post piers typically use 8-12 inch diameter Sonotube forms at 36-48 inches deep.
Always verify footing dimensions with local building codes or a structural engineer.