FOI has in different studies and computer programs (including SWERISK) used algorithms for ballistics and simplified ways to calculate fragmentation of warheads. In this documentation some of the algorithms and the methods are described. In order to calculate the range of the fragments to determine for example area of risk or effect of the fragment, some parameters are needed. This is best done by numerous experiments but can also be calculated theoretically. Mass distribution, the ejection velocity and ejection angle can be calculated using formulas and input material data. These can be used to determine the effect and area of risk by ballistics calculations. This report primarily aims to describe fragmentation and ballistics for the purpose of assessing areas of risk.