This easy to use spreadsheet tool created by Atkins for the BCSA and Tata Steel (formerly Corus) provides initial estimates of flange areas and web thicknesses for typical steel composite bridge cross sections. It is consistent with the latest SCI guidance on composite highway bridge design, and the plate sizes were derived using the Eurocodes and relevant UK National Annexes. The scope includes simply supported and continuous plate girders for both multi-girder and ladder decks. The spreadsheet tool accounts for the differences between inner and outer girders, and provides both elastic and plastic designs. It is accompanied by a helpful User Manual explaining exactly what the tool is, and how to use it. A series of design charts are also available to facilitate manual calculation if desired.