Net Revenue Retention NRR
How much recurring revenue this year's cohort of existing customers grew or shrank to, counting their upsells, downgrades, and cancellations but not any brand-new customers.
The fork, why two teams get different numbers
The single most gamed SaaS metric, and the forks are all in the denominator and the window. (1) COHORT: NRR must measure only the customers present at the start, new logos are excluded; the widespread error is to compute (ending total MRR / starting total MRR), which sneaks new-customer revenue into a "retention" number. (2) WINDOW: trailing-12-month cohort NRR vs a single month's net churn annualized (quarterly ×4, monthly ^12), annualizing a strong quarter overstates. (3) PRICE INCREASES counted as expansion (see Expansion MRR). (4) FX: for multi-currency bases, holding rates constant vs marking to spot moves NRR by whole points. Investors read the trailing-12 cohort number; internal dashboards often show the annualized monthly one.
The trap
The denominator swap.
- The full trap, worked on a real export
- Every formula variant, spelled out
- The reconciliation anchor, what to tie it to and when to refuse
Reference: SaaS operating-metric convention (no single standards body)