SaaS Metrics Guide: ARR, MRR, Churn, NRR, and LTV Explained
Six SaaS metrics drive almost all investor conversations: ARR, MRR, logo churn, net revenue retention, LTV, and CAC payback period. Understanding how they connect and what good looks like at each stage is foundational.
ARR and MRR: the difference and why it matters
Monthly Recurring Revenue (MRR) is the normalised monthly value of all active subscriptions. Annual Recurring Revenue (ARR) = MRR x 12. Both exclude one-time revenue (implementation fees, professional services) because that revenue does not recur. Including one-time revenue in your ARR figure is a red flag investors watch for.
New MRR, Expansion MRR, Churned MRR, and Net New MRR are the four components of MRR movement. New MRR comes from new customers. Expansion MRR comes from upsells and seat additions to existing customers. Churned MRR is lost from cancellations and downgrades. Net New MRR = New + Expansion - Churned. Tracking these separately shows whether growth is driven by acquisition or expansion, and how well you retain and grow existing customers.
Churn rate: logo churn vs. revenue churn
Logo churn (customer churn) = number of customers lost in a period divided by total customers at the start of the period. Revenue churn = MRR lost from churned customers divided by total MRR at the start of the period. A company can have high logo churn but low revenue churn if the churning customers are small and the retained customers are growing.
Gross revenue churn measures MRR lost from cancellations and downgrades only. Net revenue churn (or net revenue retention) subtracts expansion MRR from the same cohort. Net revenue retention above 100% means your existing customers are growing faster than you are losing to churn. This is the ideal state: the existing customer base grows without new customer acquisition.
Acceptable churn benchmarks: for SMB SaaS (average contract value under $5k/year), 2-3% monthly gross revenue churn is acceptable; best-in-class is under 1%. For mid-market and enterprise (ACV over $25k/year), target under 1% monthly. Annual contracts with multi-year commitments naturally produce lower measured monthly churn.
Net Revenue Retention: the most important SaaS metric
NRR (Net Revenue Retention, also called Net Dollar Retention) = MRR from a cohort of customers at month 12 divided by their MRR at month 0, including expansion from upsells and subtracting churn and contraction. It measures how much your existing customer base grows (or shrinks) over one year without any new customer acquisition.
NRR above 120% means your existing customers generate 20% more revenue annually just from expansion. This makes revenue growth more efficient: each new customer adds not just their initial contract value but a growing annuity as they expand. Benchmark: 100%+ NRR is the floor for a scalable SaaS business; 120%+ is best-in-class; 140%+ (rare) suggests a product deeply embedded in mission-critical workflows.
NRR is a leading indicator of eventual market leadership. High NRR companies reach net negative burn before high-churn companies with equivalent growth, because their existing base generates enough expansion revenue to offset acquisition costs.
Quick Ratio: growth efficiency in one number
The SaaS Quick Ratio = (New MRR + Expansion MRR) / (Churned MRR + Contraction MRR). It measures how much new MRR you generate for every $1 of MRR you lose. A Quick Ratio of 4 means you add $4 of new MRR for every $1 churned. Benchmark: 4+ is good for a growing startup; above 4 is excellent.
A declining Quick Ratio is a warning sign that churn is accelerating relative to new growth, even if absolute revenue is still growing. Investors track QR trends as carefully as absolute ARR numbers.
Cohort analysis: the tool that reveals the truth
Cohort analysis groups customers by acquisition month and tracks their revenue (or retention) over time. It reveals patterns invisible in aggregate metrics: are customers acquired in Q1 2025 retaining better than customers acquired in Q1 2024? Is revenue from 2024 cohorts expanding or contracting at month 12?
The most useful cohort chart for investors: a revenue retention table showing each cohort's MRR as a percentage of their initial MRR at months 1, 3, 6, 12, 18, and 24. Cohorts that stabilise above 100% (due to expansion) are the signature of strong product-market fit and NRR above 100%.
Related: Startup Metrics: Complete Guide • All Articles • The Raise Ready Book
Ready to put this into practice?
Start the Founder Assessment