Design a fin plate connection to a hollow steel column - a circular (CHS) or rectangular (RHS) tube - to Eurocode 3 (EN 1993-1-8 Chapter 7), CIDECT Design Guide 9 and SCI P358. The calculator checks the range of validity, the fin plate (gross/net/block shear and bending), the eccentric weld of the plate to the tube wall, the column wall local shear, the punching-shear limit (so the plate yields before it punches a thin tube) and the chord-face plastification of the tube, each with its utilisation and a clear PASS/FAIL on an interactive 3D model.