NRR (Net Revenue Retention)

NRR = (starting cohort ARR + expansion − contraction − churn) / starting cohort ARR, measured over twelve months. Above 110% is durable; above 120% is best-in-class. The single most-cited SaaS health metric, but easy to flatter: check the cohort definition, whether net-new logos are excluded properly, and whether expansion is captured at the right point in the renewal cycle.