  We describe a major extension of the SOFTSUSY spectrum calculator to include
the calculation of the decays, branching ratios and lifetimes of sparticles
into lighter sparticles, covering the next-to-minimal supersymmetric standard
model (NMSSM) as well as the minimal supersymmetric standard model (MSSM). This
document acts as a manual for the new version of SOFTSUSY, which includes the
calculation of sparticle decays. We present a comprehensive collection of
explicit expressions used by the program for the various partial widths of the
different decay modes in the appendix.
