Formula
(Expansion MRR - Churned & Contracted MRR) / Starting MRR x 100
How to measure
Subtract churned and contracted MRR from expansion MRR for a cohort, then divide by that cohort's starting MRR.
Why track it
Achieving negative churn means the existing customer base grows revenue even with zero new customers, one of the strongest efficiency signals in SaaS.
Example
A cohort with $10,000 in expansion against $6,000 in churn and contraction, on a $200,000 base, reports +2% negative net churn.