Steel column stress calculation
Per your effective column length (1.5m) and radius of gyration (16mm), your Slenderness ratio 93.8 is so close to the critical value 99.3.
In order for the calculator to have a smooth transition between elastic (Euler) and inelastic buckling, you need to set the proportional limit to one half (0.5) the value of the Yield stress. This will account for the max amount of residual stresses in cold rolled steel and give the most conservative results.
In your case, if you set the Yield Stress to 235MPa, then please enter 167.5 MPa as the Proportional Limit.