I'm testing out SolidWorks natural frequency FEA. I've made a simple cantilever beam out of Stainless Steel. I ran the simulation and am getting incorrect results for the natural frequencies compared to what online and hand calculations are showing. It seems like the first natural frequency match, but the subsequent ones are incorrect. Any help would be appreciated, thanks.

The hand calcs are only calculating the resonant frequencies in a certain plane. The FEA calculates vibration modes in general 3D space.

So make sure you are filtering through the modes to find the vibration modes corresponding to vibration in the correct plane. You may need to increase the number of frequencies the study is solving for because of this. Then I would expect them to match within a reasonable margin.

There are also validation examples available for similar problem setups in SOLIDWORKS, under Help -> SOLIDWORKS Simulation - > Validation -> Verification Problems