Enter throat a, length and load: the calculator checks the weld by the EN 1993-1-8 §4.5.3.3 simplified method and tells you which throat is enough.
What it covers and what it does not. Simplified method §4.5.3.3: resistance is independent of the force direction, so the result is conservative. It does not check the parent metal next to the weld, fatigue, eccentricity or force distribution within a weld group: joints with moment need a full design, for example the directional method §4.5.3.2.
fvw,d = fu / √3 / (βw · γM2), γM2 = 1.25; βw 0.8 for S235, 0.9 for S355.
Fw,Rd = fvw,d · a per unit length, times leff and the number of welds. Minimum: a ≥ 3 mm, leff ≥ max(30 mm; 6a).
S235, a = 5 mm, L = 100 mm: fvw,d = 207.8 MPa, Fw,Rd = 103.9 kN, as in the code example.