This work summarizes recent research at Swebrec and SveBeFo. It has led to a new fragment size distribution with an unexpected ability to reproduce sieving curves of all kinds of rock and concrete/mortar that have been blasted or crushed in almost every conceivable way. The three-parameter Swebrec function is described but its parameters are not independent. Examples of curve fits are given as is some advice about the fitting procedure. Its relations to other comminution concepts such as t 10 from JKMRC are explored. How to use the Swebrec function for full-scale blasts is described, especially for large blasts where the available information is very limited. The final section treats design curves, which can predict the changes in fragmentation that are caused by changes in specific charge and other geometrical parameters of a bench blast. Evidence to the effect of confining debris at the free face is finally presented.