Terzaghi shallow-footing bearing-capacity calculator.

read the result

Keep the three bearing-capacity terms visible.

The classical shallow-footing expression separates the contribution from cohesion, surcharge at foundation level, and the soil wedge below the base. Rectangular shape factors are shown so the result can be audited instead of treated as a black-box allowable pressure.

Governing relationships

The gross ultimate pressure is q_ult = cN_cs_c + qN_qs_q + 0.5γBN_γs_γ, where q = γD_f. The calculator uses N_q = e^πtanφtan²(45° + φ/2), N_c = (N_q - 1) / tanφ, and the classical Terzaghi N_γ = 1.5(N_q - 1)tanφ. At φ = 0, N_c is set to 5.14.

What still needs a full geotechnical design

• This is a Terzaghi general-shear screen with a rectangular footing, concentric vertical load, and level ground. It does not apply code-specific depth, inclination, ground-slope, or base-inclination factors.
• Groundwater, layered soil, frost, scour, seismic effects, partial saturation, settlement, and serviceability are excluded.
• Use the applicable code and geotechnical report to select drained or undrained parameters, failure model, factor of safety, and the correct gross/net pressure basis.