WPurlin is a cold-formed steel purlin and girts design tool. The software considers bending moments and shear forces for the design and optimization of "Z" and "C" cold-formed members. The structural model for purlins/girts can be chosen between simple or continuous beam. The spans may have different lengths, so that the design does not need to be simplified by considering constant length for all the spans. The load combinations and resistance factors follow the AISI 2001 code, according to the ASD scope (Allowable Strength Design), and can be checked out in the report created after some design and optimization is carried out in the software. The concepts of effective properties of cold-formed sections prescribed in the AISI code are taken into account in order to carry out the structural elements design properly. The main advantage of WPurlin is the optimization of the pieces weight, done automatically based on the cold-formed profiles database of the client (in the demo version, the optimization is done considering the cold-formed profiles database built into the software for tests purpose). WPurlin can be customized according to the client needs. We list below some possible features to be included in a registered version: -The logo of your company in the reports; -Use other versions of AISI design codes, including the LRFD (Load and Resistance Factor Design) scope; -Use of many structural steel types; -Compute many purlins/girts lines for a same roof/wall panel; -Detailed report, with design process details, showing equations used on the design, step-by-step; -Use your own profile databases, allowing you to obtain always the lower possible weight for your girts and purlins, respecting the AISI design code for cold-formed steel members.