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Timber Column Euler Buckling Calculator

Calculate the critical Euler buckling load for a slender timber column.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax
9.84 ft
Schematic, drawn to the proportions you entered — not to scale on screen.

Critical buckling load

1206.28 kN

High confidence

Running these inputs gives 1206 kN as the critical buckling load. Note that moment of inertia i (×10⁶ mm⁴) sits at the low end of the range this calculator was checked against, so treat the output as indicative rather than settled. Currently reading for United States under IRC 2024 — pick a different market above and the figures re-cast accordingly.

Add the equipment this sizes

This result is a specification — 1,206.285 kN — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Euler's critical buckling load formula: Pcr = π²EI/(KL)², where K is the effective length factor for the column's end conditions

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

What does the effective length factor K represent?
K accounts for how the column's ends are restrained: 0.5 for fixed-fixed, 0.7 for fixed-pinned, 1.0 for pinned-pinned (the theoretical baseline), and 2.0 for a fixed-free cantilever column — these are Euler's classical end-condition cases.
Does this account for real-world timber column failure?
No — Euler buckling is a theoretical elastic instability formula. Real timber columns must also be checked against the NDS column stability factor (CP) provisions, which blend elastic buckling behavior with the wood's compression-parallel-to-grain strength.
Why does unbraced length have such a large effect on capacity?
Unbraced length is squared in the (KL)² term, so doubling the unbraced length between points of lateral support cuts the critical buckling load to one-quarter — adding a mid-height brace can substantially increase a slender column's capacity.