MRR and ARR Explained: The Metrics That Matter for SaaS Businesses
Monthly and Annual Recurring Revenue are the heartbeat metrics for any subscription business. Here's how to calculate and track them properly.
What is MRR?
Monthly Recurring Revenue is the predictable revenue you can expect each month from active subscriptions. It excludes one-time fees, setup charges or non-recurring revenue.
What is ARR?
Annual Recurring Revenue is simply MRR multiplied by 12 — used more often by larger SaaS companies or those with annual billing cycles, as it gives a cleaner annualized view.
The Components of MRR Movement
New MRR (from new customers), Expansion MRR (upgrades from existing customers), Contraction MRR (downgrades), and Churned MRR (cancellations) together explain your month-over-month MRR change. Tracking each separately reveals far more than the net number alone.
Why Accounting Software Alone Won't Show You This
Standard P&L reports show total revenue recognized for the period — but they don't separate new vs. expansion vs. churned MRR. This requires a parallel tracking system, often built from your billing platform data (Stripe, Chargebee, etc.) reconciled against your books.
Revenue Recognition for Annual Plans
If a customer pays $1,200 upfront for an annual plan, that's not $1,200 of revenue in month one — it's $100/month recognized over 12 months, with the remainder sitting as deferred revenue on your balance sheet. Getting this right matters for both GAAP compliance and accurate MRR reporting.
Net Revenue Retention (NRR)
NRR measures how your existing customer base's revenue changes over a period, accounting for expansions, contractions and churn — but excluding new customer revenue. An NRR above 100% means your existing customers are growing in value even before counting new sales, a strong signal for investors.
CAC and LTV
Customer Acquisition Cost (CAC) and Lifetime Value (LTV) work alongside MRR to tell the full growth story. A healthy LTV:CAC ratio (often cited as 3:1 or higher) suggests your growth is sustainable — but calculating LTV accurately requires the same revenue recognition discipline as MRR itself.
Cohort Analysis
Beyond a single MRR number, tracking how cohorts of customers (grouped by signup month) behave over time — their retention curve, expansion patterns — reveals whether your unit economics are improving or deteriorating as you scale, information a single point-in-time MRR figure can't show.
