Concrete Footing Calculator
Footing volume and optional bags from finished bag yield.
How it works
This is concrete quantity from the dimensions you supply. Rectangular elements use length × width × depth; round elements use π × diameter² / 4 × height. Choose dimensions from your project before estimating the quantity.
Related calculators
How the Concrete Footing Calculator works
Estimate concrete for a footing, pad or circular pier using dimensions from your plan. Length is entered in feet, while width, depth and pier diameter are entered in inches in the US unit system.
Feet and inches to cubic yards
A 40 ft continuous footing that is 18 in wide and 8 in deep contains 40 × (18/12) × (8/12) = 40 ft³. Dividing by 27 gives 1.481 yd³ net; a 10% allowance produces about 1.630 yd³ for the order.
For round piers, use π × diameter² / 4 × height, then multiply by the number of identical piers. Split different shapes or depths into separate calculations and avoid counting intersecting footing volumes twice.
Bags require finished yield
The optional yield field is finished mixed concrete volume per bag in the displayed unit. If a label gives 0.6 ft³, convert that to 0.6/27 = 0.022222… yd³ per bag for the US field. Leave yield empty for ready-mixed volume only.
Bag yield and ground irregularity are distinct from footing design. Supply the specified dimensions first, then use the quantity for ordering. Estimate reinforcement schedule weight in the rebar calculator.
FAQ
Does this tell me how wide a footing should be? expand_more
No. Enter dimensions from the design; the calculator supplies the concrete quantity.
Can I use the dry bag weight as yield? expand_more
No. Pounds describe mass, while the yield field needs the finished concrete volume.
Why add an allowance? expand_more
Specified geometry gives net volume; the entered allowance is a separate purchasing addition for the conditions you have assessed.