+1 combat result for each wound inflicted.

Each side's basic combat result is equal to the wounds caused in the close combat phase, regardless of source (except wounds that are caused by friendly models). It's important to tally up the number of wounds, rather than the number of casualties – most characters and monsters have more than one wound and it can take several rounds of combat to slay them. Note that any Wounds that are saved by armour, ward save or other special rules do not count towards to the result.