Footing Size Calculator

Calculate foundation footing dimensions and concrete volume based on load and soil capacity.

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What This Calculator Does

Calculate foundation footing dimensions and concrete volume based on load and soil capacity.

It combines Total Load, Soil Bearing Capacity, Footing Shape, Footing Depth to estimate Footing Side Length, Required Bearing Area, Concrete Volume.

Formula & Method

Required bearing area is

A_r=\frac{Load}{SoilCapacity}

. Square footing side

s=\sqrt{A_r}

; round footing diameter

d=2\sqrt{\frac{A_r}{\pi}}

. Concrete volume

V=A\cdot depth

Notation used in the formulas: $R$ = Footing Side Length; $x_{1}$ = Total Load; $x_{2}$ = Soil Bearing Capacity; $x_{3}$ = Footing Shape; $x_{4}$ = Footing Depth.

Method summary: inputs are normalized to consistent units, core equations are evaluated, then secondary values are derived and rounded for display.

Use this calculator for quick scenario analysis. Start with baseline values, change one driver at a time, and compare how sensitive the results are to each input shown above.

Reference Book

Mechanics of Materials

SI Edition

Russell C. Hibbeler · Pearson

A standard reference for stress, strain, section properties, beam behavior, and material deformation.

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Inputs Used

Total Load: Total load the footing must support
Soil Bearing Capacity: Allowable soil bearing pressure
Footing Shape: Used directly in the calculation.
Footing Depth: Used directly in the calculation.

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