Column Load Calculator Formula

Understand the math behind the column load calculator. Each variable explained with a worked example.

Formulas Used

Maximum Load

max_load_lbs = cross_area * allowable_stress

Maximum Load

max_load_kips = cross_area * allowable_stress / 1000

Cross-Section Area

area = cross_area

Variables

VariableDescriptionDefault
col_widthColumn Width(in)6
col_depthColumn Depth(in)6
allowable_stressAllowable Compressive Stress(psi)1000
cross_areaDerived value= col_width * col_depthcalculated

How It Works

Column Axial Load

P = A x Fc

Where A is the cross-sectional area and Fc is the allowable compressive stress. This applies to short columns where buckling is not a concern. For slender columns, the Euler buckling formula must be used to reduce the allowable load.

Worked Example

6x6 wood column with 1,000 psi allowable stress.

col_width = 6col_depth = 6allowable_stress = 1000
  1. 01Area = 6 x 6 = 36 sq in
  2. 02Max load = 36 x 1000 = 36,000 lbs = 36 kips
  3. 03Note: actual lumber is 5.5 x 5.5 so use 30.25 sq in.

Ready to run the numbers?

Open Column Load Calculator