Footing Calculator

For strip footings: Length × Width × Depth = cubic feet, then divide by 27 for cubic yards. For spread footings: L × W × D per footing × number of footings. For round piers: π × radius² × depth × quantity. Add 10% for waste and irregular excavation. Order ready-mix in full yard increments.

Footings must extend below frost line—varies from 12" in southern US to 48"+ in northern regions. Minimum depth is typically 12" below undisturbed soil. Pier footings often require 36-48" depth. Always check local building codes for exact requirements based on your climate zone.

Ready-mix concrete: USA $120-180/yd³; Canada C$150-220; UK £80-120/m³; Australia A$200-350/m³. Bagged concrete: $4-6 per 80lb bag (~0.6 cu ft). Total installed: $200-400/yd³. Small jobs may have minimum delivery charges.

Most building codes require rebar in footings. Typical: 2 horizontal #4 bars continuous in strip footings. Spread footings: #4 bars both directions at 12" OC. Even if not required, rebar adds minimal cost and significant strength. Follow local codes or engineering specs.

Standard residential strip footing is twice the wall width. An 8" wall needs 16" footing. Depth should be at least equal to projection beyond wall. Larger footings needed for poor soil or heavy loads. Always check local building codes for minimum requirements.

Deck pier footings are typically 12" diameter for light loads, 18" for heavy. Depth must reach below frost line—36" minimum in many areas. Use cardboard tube forms (Sonotube). One 12" × 36" pier needs about 0.15 cubic yards of concrete. Space piers 6-8 ft apart per beam requirements.