NDR vs. GRR: The Two Retention Numbers That Matter
Two canonical formulas:
– Gross Revenue Retention (GRR) = (Starting ARR − Contraction − Churn) ÷ Starting ARR
– Net Dollar Retention (NDR) = (Starting ARR + Expansion − Contraction − Churn) ÷ Starting ARR
GRR shows how well you keep what you have. NDR shows whether existing customers grow enough to offset losses. They answer different questions; track both.