Friction Stir Welding (FSW) has received significant attention from the engineering community since the first weld was made in 1991. Much of the R&D effort has been directed towards possible aerospace applications. Aerospace components demand a very high level of reliability, so it is that critical that the aerospace usage of FSW is with well-documented welding procedures that have a high level of quality and repeatability. Progress towards this goal has been made in laboratory research. Laboratory and factory knowledge should be further enhanced by a clear synthesis of the process based upon an analytical understanding of material deformation and heat flow. TWI is developing FSW Utility Tools (FswUTs) at a range of levels for use by all FSW engineers. Simple FswUTs have been written for application in spreadsheets for rapid use at all levels of FSW engineering. These are able to provide clear assessment of the mechanical requirements for good FSWs. More complicated FswUTs have been developed for application in advanced simulation software for prediction of FSW integrity through consideration of material redistribution during welding. The TWI FswUTs will be demonstrated in this presentation.