Estimate square footing size, rectangular footing size, round footing diameter, soil bearing pressure, footing utilization, required bearing area, concrete volume, and concrete bags. Use this footing size calculator for deck posts, porch posts, columns, piers, beam supports, small foundations, and preliminary structural planning.
Total load:
The calculator adds post or column load, beam reaction, and extra load, then applies the selected load factor.
Required area:
The calculator divides total load by allowable soil bearing to estimate the minimum bearing area.
Required size:
The calculator converts required area into a round diameter, square side length, or rectangular footing size.
Concrete volume:
The calculator uses footing area and thickness to estimate concrete volume, concrete yards, and bag count.
A footing size calculator helps estimate how large a footing should be to spread post or column loads into the soil.
It can help compare total load, required bearing area, existing footing pressure, soil utilization, concrete volume, concrete bags, and approximate footing dimensions.
Your result shows estimated total footing load, allowable soil bearing, required footing area, recommended round diameter, recommended square side, existing footing area, bearing pressure, footing utilization, concrete volume, and estimated concrete bags. These are planning estimates only.
Divide the total load on the footing by the allowable soil bearing pressure. The result is the minimum required bearing area before applying code, frost, reinforcement, and construction requirements.
A deck post footing depends on deck load, post spacing, tributary area, soil bearing, frost depth, and local deck code. This calculator estimates bearing area, but local requirements may require a larger footing.
Allowable soil bearing is the estimated pressure the soil can safely support, usually expressed in pounds per square foot. Soil type and local code can change this value.
No. Final footing design should account for local code, frost depth, soil conditions, settlement, concrete strength, reinforcement, uplift, lateral loads, eccentric loads, and professional review when needed.