Net revenue retention (NRR)

The share of recurring revenue kept from an existing customer base over a year including expansion, net of churn and downgrades, expressed as a percentage.

Above 100% means the base grows without a single new customer, which is why software and subscription buyers pay premium multiples for it and scrutinize it in diligence.

In numbers: A SaaS business keeping $95k of every $100k cohort and expanding it to $110k has 110% net revenue retention.