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Cantilever Beam Calculator

Computes fixed-end moment, shear and free-end deflection for a cantilever under point or distributed load.

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How to use this calculator

Enter Values

Minimum 0

Minimum 0

Minimum 0

Minimum 0

Enter your values and press Calculate to see results.

Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.

How to use this calculator

  1. Enter the cantilever length L — the projection from the fixed support.
  2. Add a point load at the free end and/or a uniform load along the length.
  3. Optionally add E and I to also get the free-end deflection.
  4. Read the maximum moment and shear (at the support) and, if provided, the tip deflection.

How it works

The Cantilever Beam Calculator analyses a beam built in (fixed) at one end and free at the other.

Both the bending moment and shear peak at the fixed support: a free-end point load gives M = P·L and V = P; a uniform load gives M = w·L²/2 and V = w·L. Deflection is largest at the free end — PL³/3EI for a tip load and wL⁴/8EI for a uniform load.

Worked example

3 m cantilever, 8 kN at the tip. Support moment = 8×3 = 24 kN·m; support shear = 8 kN. With E = 200 GPa and I = 5000 cm⁴, tip deflection = 8000×3³ / (3×10×10⁶) ≈ 7.2 mm.

Tips

  • Cantilevers deflect far more than simply supported beams of the same span — the tip moves with L³ to L⁴.
  • The fixed connection must actually develop the support moment; a weak fixing makes the calculation invalid.

Frequently asked questions

Why are the moment and shear largest at the support?

A cantilever carries its entire load back to the single fixed support, so the bending moment and shear both build up to a maximum there and fall to zero at the free end.

Do I have to enter E and I?

No — leave them blank and you'll still get the moment and shear. Add them only when you also want the free-end deflection.

Can I use these results for final design?

No. These calculators are for first-pass sizing, checking and learning. They assume ideal supports, static loads and elastic behaviour, and they don't apply load factors, member capacity, buckling or connection checks. Always verify against the relevant design code (e.g. AS 4100, AS 1170, Eurocode) and have a qualified engineer sign off structural work.

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Cite this tool

Zerdly. (2026). Cantilever Beam Calculator. Retrieved from https://www.zerdly.com/tools/cantilever-beam-calculator/

Tip: Enter any known values to calculate the remaining results.

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