Concrete Footing Calculator

Calculate concrete volume and ordering for a uniform rectangular strip footing.

Foundation concrete

Estimate a continuous rectangular footing

Enter footing length and width in feet and depth in inches, or switch to metric units. The calculator multiplies the uniform cross-section by total length, converts the result to cubic yards or cubic meters, and adds the selected order allowance. Results include common bag counts, ready-mix guidance, truck planning, rough cost, formula details, and a supplier handoff summary.

Starting size20 ft long × 1 ft wide
Starting depth12 in
Order allowance5% default

Measure each footing section separately

This route is designed for a strip or pad footing with a constant rectangular cross-section. Stepped footings, keyways, widened pads, grade beams, changes in elevation, and intersecting runs should be divided into measurable sections and added together. Excavation dimensions may be larger than the specified concrete dimensions, so calculate from the actual footing detail rather than trench size unless the trench itself forms the concrete.

Footing width, thickness, bearing depth, reinforcement, and concrete strength are structural and code decisions. The planner can surface state-level frost-line context from a US ZIP code, but local adopted code, soil bearing, loads, seismic conditions, and engineering documents remain controlling. Confirm dimensions and reinforcement before ordering concrete.

Footing calculator FAQ

How much concrete is in a 20 ft × 12 in × 12 in footing?

The design volume is about 0.74 cubic yard. With a 5% allowance, the planning order is about 0.78 cubic yard.

Does the calculator determine footing size?

No. It calculates volume from dimensions you provide. Required footing dimensions and reinforcement must come from applicable plans, code, soil conditions, and engineering requirements.

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