Churn & Retention Calculator

Enter your customer counts and MRR at the start/end of a period to see customer churn, revenue churn, and net revenue retention (NRR).

Customer churn

How many customers you lost, as a share of who you started with (new customers acquired during the period don't count against this).

Customers at start of period

Customers lost during period

New customers added

Customer churn rate

–

Ending customers

–

Revenue churn & retention

MRR from your existing customer base only — exclude MRR from customers you acquired new this period, since that's growth, not retention.

Starting MRR (existing customers)

Ending MRR from those same customers

Of which: expansion MRR (upgrades)

Of which: contraction + churned MRR (downgrades + cancellations)

Gross revenue churn

–

Net revenue retention (NRR)

–

NRR above 100% means expansion from existing customers outpaces downgrades and cancellations — the gold standard for "grow without new sales." Below 100% means you're leaking revenue from your base even before counting new customers.

Customer churn vs. revenue churn vs. NRR

These three numbers answer different questions, and mixing them up is the single most common metrics mistake in SaaS reporting. Customer (logo) churn counts accounts lost, regardless of size — losing your biggest and smallest customer counts the same. Revenue churn weights by dollars, so losing one large account can outweigh losing ten small ones. Net revenue retention (NRR) goes further and nets in expansion — upgrades and cross-sells from customers who stayed — against the downgrades and cancellations.

How to use it

Logo churn matters most for high-volume, low-price products where every customer is roughly similar in size.
Revenue churn and NRR matter most once you have meaningfully different account sizes — logo churn alone can hide that you're losing your most valuable customers.
NRR above 100% is the benchmark best-in-class SaaS companies target — it means the existing customer base grows revenue on its own, before a single new customer is added.

Common mistakes

Including newly acquired customers in the churn denominator — churn should only be measured against who you already had, not who you ended the period with.
Reporting only logo churn when account sizes vary widely, which can make things look fine while revenue quietly concentrates and then craters when one large account leaves.
Forgetting that gross revenue churn and NRR are computed from *existing-customer* MRR only — mixing in new-customer MRR inflates retention numbers and makes them meaningless for trend tracking.