Cantilever beam calculator
Fixed at one end, free at the other. Add any combination of loads, choose a section, and read wall reaction, fixing moment, tip deflection and stress. Compare against the closed-form formulas on the formulas page.
About this case
How to use this cantilever beam calculator
The preset is a fixed-left cantilever. Set the length, then add loads: tip point load, tip moment, uniform load, triangular load, or any combination. Drag loads to reposition them. The section library includes rectangles, hollow sections, and I-beams; materials include steel, aluminum, concrete and timber.
Self-weight toggles the beam's own weight as a UDL from the section area and material density. Spring supports can be added along the length to model elastic foundations or partial fixity.
Reading the results for a cantilever design
The wall reaction force and wall fixing moment are exactly what the bracket, weld or embedment must resist. The tip deflection against L/180 is the common serviceability check; note that for the same total load, a tip load deflects 8/3 times more than a uniform load, so converting a spread-out load into a single tip value is conservative by a wide margin but useful as a bound.
Bending stress is reported at the wall (maximum) and at any load point. Average shear stress is V/A at the wall; for I-sections the web shear is higher — use a code-based tool for detailed web checks.
Common cantilever mistakes this tool helps you catch
Modelling a genuinely distributed load as a tip load "to be safe" is defensible for a bound but can hide where the real maximum stress sits when the load actually spreads over the member. The reverse is the dangerous one: modelling a concentrated load as an equivalent UDL halves the apparent wall moment and is unconservative. Second error: applying the tip-deflection formula to a load that is not at the tip; the closed form changes, and dragging the load in the calculator shows the corrected value instantly.