Euler column buckling calculator

Buckling is a column bowing sideways under compression before the material reaches its strength. Pick the end condition and enter the column data.

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How to use it

  1. Enter elastic modulus, least moment of inertia, column length and end conditions.
  2. The result appears straight away and updates as you edit.
  3. Copy the result, or copy a link that keeps the same values to share it.

How it is calculated

Pcr = π² E I ÷ (K L)². K = 1 pinned both ends, 2 fixed and free, 0.5 fixed both ends, 0.699 fixed and pinned (theoretical values).

Example

Inputs: Elastic modulus = 200 GPa, Least moment of inertia = 1,000 cm⁴, Column length = 3 m, End conditions = Pinned, pinned (K = 1). Result: Critical buckling load: 2,193.25 kN; Effective length: 3 m; Effective length factor K: 1.

Limits and caveats

  • Euler applies to slender columns only; short columns fail by yielding first.
  • Leaves out safety factors, eccentricity and initial crookedness that design codes include.

Questions about this tool

Which moment of inertia should I use?

The smaller of the two axes, because the column buckles about its weakest axis.

When does the Euler formula not apply?

When the stress Pcr ÷ A is above the proportional limit of the material, as in short or stocky columns.

Why do codes use different K values?

Full fixity is hard to achieve in practice, so some codes recommend slightly higher design values, such as 0.65 instead of 0.5.