Calculate cubic yards and bags of concrete for continuous strip footings and pad footings. Width and depth entered in inches, length in feet.
Set footing forms to exact elevation with a rotating laser level.
Shop Express Tools →Footing concrete volume = Length (ft) × Width (ft) × Depth (ft) ÷ 27 for cubic yards. A standard 16" wide × 8" deep continuous footing at 50 feet long requires about 2.47 CY of concrete. Add 10% for waste. Always go below the frost line for your area.
Footings transfer structural loads from the building to the soil. Two critical requirements govern footing design: depth below frost line (to prevent heave from freeze-thaw cycles) and size relative to soil bearing capacity (to prevent settlement). The formula for footing volume is straightforward:
Concrete strength for footings is typically 2,500–3,000 PSI minimum per ACI 318 for residential applications. Most contractors use 3,000 PSI for footings. Rebar requirements depend on soil conditions and structural loading — minimum is typically two #4 bars in a continuous footing per most residential codes, but your structural drawings should specify the exact reinforcement.
| Region | Frost Depth | Example Cities |
|---|---|---|
| Deep South / Gulf Coast | 0–12 inches | Miami, New Orleans, Houston |
| Mid-South / Southwest | 12–18 inches | Atlanta, Dallas, Phoenix |
| Mid-Atlantic | 18–30 inches | Washington DC, Charlotte |
| Pacific Northwest | 12–24 inches | Seattle, Portland |
| Midwest | 30–48 inches | Chicago, St. Louis, Denver |
| Upper Midwest / Northeast | 48–54 inches | Minneapolis, Boston, Detroit |
| Northern states / Mountains | 54–72 inches | Duluth, Anchorage, Flagstaff |
Always verify with your local building department — local amendments may require deeper footings than the regional standard.
Document footing inspections with Sitemark →
Log footing dimensions, rebar placement, and inspector sign-off with GPS location and photos. Required for most municipal inspections and permanent project records.
Start free trialFootings must extend below the frost line to prevent heaving. Frost depth varies by location: 12 inches in the deep South, up to 60 inches in northern states. Check your local building code for the required frost depth.
A footing should be at least as wide as the wall it supports, typically 1.5–2× the wall thickness. For an 8-inch wall, a 16-inch wide footing is standard. Your structural engineer will specify based on soil bearing capacity.
A continuous (strip) footing runs the full length of a wall and is used for load-bearing walls. A pad footing (isolated footing) supports a single column or post. Both are calculated the same way — volume = length × width × depth.
Laser levels like the Spectra HL760 or Topcon RL-H5A are used to set footing forms at a consistent elevation. This is critical for structural integrity and ease of building the walls above.