Win rate
Win rate is the share of opportunities closed in a period that were won, counted either by number of deals or by value.
In practice
Win rate drives capacity and pipeline planning: the lower it is, the more pipeline each target needs. It also shows where the process breaks when you cut it by segment, source, competitor or rep.
Win rate = closed-won ÷ (closed-won + closed-lost), for opportunities closed in the period. State whether you count by deal or by value, and whether opportunities closed as no decision are included, then keep that definition fixed so trends stay comparable.