The stress distribution in fillet weldedT‐joints was investigated with computer modeling. The finite element method was used for the analysis ofT‐joints in the plane stress condition, under static load. Photoelastic stress measurement was employed to check the validity of the computer calculations. Following the American Welding Society (AWS) welding design procedure, the AWS permissible design loads were used as a reference for the stress analysis. The ultimate strength of the weldedT‐joints was determined when the plastic hinge first occurred in the joints during the loading. A set of newly designed curves for fillet weldedT‐joints with various degrees of flange flexibility were obtained. The curves were compared with the AWS Code and the American Institute of Steel Construction (AISC) Specifications. As a result, a revision in the application of these two design concepts was conceived. The full strength weld size was also evaluated with different web lengths and flange flexibilities according to the AWS and AISC design procedures. It is suggested that the industry is at a point where a more accurate weld design concept is needed.