What it is
NRR (net revenue retention) measures whether the starting customer cohort grows or shrinks after expansion, contraction, and churn. Above 100% means the installed base expanded enough to more than offset losses.
How it’s calculated
Classic form: (starting ARR + expansion − contraction − churn) ÷ starting ARR — excluding new logos. Cohort timing (month, quarter) and whether price increases count as expansion must be documented.
Where it breaks
NRR breaks when expansion is taken from CRM and churn from billing, when new logos sneak into the cohort, or when GRR and NRR cannot be reproduced from the same waterfall movements.
In the board pack
Always pair NRR with GRR. NRR alone can hide a weak retention story behind expansion. See GRR vs NRR.
Keep the written definition stable across close, the board pack, and diligence so the same word never means two math models.