Subscription Metrics That Matter
The five essential subscription metrics are MRR (monthly recurring revenue), ARR (annual recurring revenue), LTV (lifetime value), CAC (customer acquisition cost), and NRR (net revenue retention). Together they reveal whether a subscription business is growing efficiently or burning cash. A healthy business targets an LTV:CAC ratio above 3:1 and NRR above 100%.
The Dashboard That Runs the Business
Every subscription business is governed by a handful of interconnected metrics. Get these right and you have a real-time operating dashboard that tells you exactly where the business is healthy, where it's leaking, and where the highest-leverage opportunities are. Get them wrong — or track the wrong ones — and you're flying blind with a false sense of confidence.
This guide defines each essential metric, shows how to calculate it, explains what it actually tells you, and flags the common mistakes that mislead operators.
How Do You Calculate MRR for a Subscription Business?
The total predictable revenue the business generates each month from active subscriptions.
If you have 500 subscribers at £20/month and 200 at £50/month: MRR = (500 × £20) + (200 × £50) = £20,000.
Why it matters: MRR is the heartbeat metric. It tells you the current run-rate of the business. More importantly, breaking MRR into its components reveals the dynamics underneath:
New MRR: Revenue from subscribers who joined this month. Expansion MRR: Additional revenue from existing subscribers who upgraded or added services. Contraction MRR: Lost revenue from existing subscribers who downgraded. Churned MRR: Lost revenue from subscribers who cancelled or whose payments failed.
A positive Net New MRR means the business is growing. A negative one means it's shrinking — regardless of how many new subscribers joined.
Common mistake: Counting one-time fees, setup charges, or non-recurring revenue in MRR. MRR must be purely recurring.
ARR — Annual Recurring Revenue
MRR × 12. The annualised run-rate of recurring revenue.
Why it matters: ARR is the standard valuation metric for B2B SaaS companies. Investors and acquirers value subscription businesses as a multiple of ARR — typically 5–15x for healthy SaaS companies. ARR is also the benchmark for growth milestones ($1M ARR, $10M ARR, $100M ARR).
When to use ARR vs MRR: B2B businesses with annual contracts typically report ARR. B2C businesses and businesses with predominantly monthly billing typically report MRR. Both are useful; ARR just smooths out monthly variation.
Common mistake: Using ARR for businesses with high monthly churn. If your monthly churn is 8%, your actual annual revenue will be far less than MRR × 12 because the subscriber base erodes throughout the year.
Churn Rate — Subscriber and Revenue
The percentage of subscribers (or MRR) lost in a period.
Why both matter: Subscriber churn and revenue churn can tell very different stories. If your cheapest-tier subscribers churn at high rates but your premium subscribers retain well, your subscriber churn may look alarming while your revenue churn is healthy. Conversely, if you lose a few large accounts, revenue churn can spike even if subscriber churn looks fine.
The cohort imperative: A blended churn rate across all subscribers hides the actual dynamics. Always measure churn by cohort — when did these subscribers join? — and by segment — which plan, channel, or geography do they belong to? This is where actionable insights live. → What Is Churn. For the complete framework on data, metrics, and experimentation, see Chapter 11. And for how pricing strategy impacts ARPU and LTV, explore our pricing guide.
Common mistake: Measuring churn only as a single monthly number without distinguishing between voluntary and involuntary churn. These require completely different solutions. → Failed Payments
LTV — Lifetime Value
The total revenue a subscriber generates over their entire relationship with the business.
Why it matters: LTV tells you how much a subscriber is worth — and therefore how much you can afford to spend to acquire one. It is the numerator in the most important ratio in subscription economics: LTV:CAC.
Nuances: The simple formula assumes constant churn and constant ARPU, which is never exactly true. More sophisticated LTV models account for churn curves (higher early, lower later), expansion revenue (ARPU increases over time as subscribers upgrade), and discount rates (a pound today is worth more than a pound in month 24).
For early-stage businesses, the simple formula is sufficient. As the business matures and has enough cohort data, build a cohort-based LTV model that tracks actual revenue generated by each cohort over time.
Common mistake: Using LTV to justify excessive acquisition spending. An LTV of £500 does not mean you should spend £500 to acquire a subscriber — because the revenue is spread over months or years, and there is always a risk the subscriber churns earlier than the average.
Subscribe & Conquer covers all five levers in depth — with worked examples, action checklists, and a 90-day implementation plan.
CAC — Customer Acquisition Cost
The fully loaded cost of acquiring one new subscriber.
Fully loaded means all costs: ad spend, content marketing costs, sales team salaries and commissions, trial/freemium costs, referral incentives, and any other cost directly attributable to acquiring new subscribers.
Why it matters: CAC determines whether your growth is sustainable. Spending £100 to acquire a subscriber with an LTV of £500 is healthy. Spending £100 to acquire a subscriber with an LTV of £80 is a slow-motion disaster.
The LTV:CAC ratio: 3:1 or higher is generally considered healthy — the subscriber generates at least three times what they cost to acquire. Below 3:1 suggests acquisition is outpacing value. Above 5:1 may indicate under-investment in growth (you could be growing faster).
Payback period: The number of months it takes for a subscriber's cumulative payments to cover their CAC. Under 12 months is strong. Under 6 months is exceptional. A long payback period means the business needs significant capital to fund growth — each new subscriber is cash-flow negative for months before becoming profitable.
Common mistake: Calculating CAC using only ad spend and ignoring sales salaries, content costs, and other acquisition-related overhead. This understates the true cost and makes unit economics look healthier than they are.
NRR — Net Revenue Retention
The percentage of revenue retained from existing subscribers after accounting for churn, contraction, and expansion.
Example: Starting MRR: £100,000. Expansion: +£8,000. Contraction: −£2,000. Churned: −£5,000. NRR = (£100,000 + £8,000 − £2,000 − £5,000) ÷ £100,000 = 101%.
Why it matters: NRR is arguably the single most important metric in a subscription business. An NRR above 100% means the existing subscriber base is growing on its own — even without adding a single new customer. The best B2B SaaS companies operate at 120%+ NRR, meaning their existing customers generate 20% more revenue year over year through upgrades and expansion alone.
An NRR below 100% means the existing base is contracting — and the business must acquire new subscribers just to maintain current revenue, before it can grow.
Common mistake: Ignoring NRR in favour of gross revenue growth. A business can show impressive top-line growth by acquiring aggressively while its existing base quietly contracts. NRR reveals whether the growth is sustainable or whether acquisition is masking a retention and expansion problem.
Vanity Metrics: What Not to Measure
Not every number that goes up is a good sign. Vanity metrics feel good but mislead.
Total sign-ups (without retention context): 10,000 sign-ups means nothing if 80% churn within 60 days. Sign-ups are IOUs, not revenue.
Gross subscriber count (without churn offset): "We have 50,000 subscribers" sounds impressive until you learn you had 48,000 last month and acquired 5,000 — meaning you lost 3,000.
App downloads (for mobile subscriptions): Downloads do not pay bills. Trial starts are closer. Paid conversions are what matters.
Social media followers or email list size: These are awareness metrics, not business metrics. They matter only if they convert to subscribers.
The antidote to vanity metrics is cohort thinking: track what happens to each group of subscribers over time, measure the revenue they actually generate, and compare it to what they cost to acquire.
How These Metrics Connect
These metrics do not operate in isolation. They form an interconnected system:
Improving retention (reducing churn) increases LTV. Higher LTV justifies higher CAC — you can afford to spend more on acquisition because each subscriber is worth more. Better pricing increases ARPU, which increases both MRR and LTV. Expansion revenue increases NRR, which means the existing base grows automatically. Payment optimisation reduces involuntary churn, which improves retention, which flows through to every other metric.
This is why the five levers must work together as a system, not as isolated initiatives.
The subscription businesses that compound are the ones where every lever reinforces every other lever. The metrics are the scoreboard that tells you whether the system is working.
Subscribe & Conquer: Metrics, Cohorts & Experimentation
Chapter 11 covers the complete metrics, cohort analysis, and experimentation framework — including the ICE prioritisation model for running experiments across pricing, retention, and acquisition simultaneously.
Subscribe & Conquer: The $50M Subscription Playbook for Unstoppable Recurring Revenue
The complete operating manual for building, fixing, and scaling a subscription business. All five revenue levers. Worked examples. A 90-day action plan. Written from the trenches of a bootstrapped $50M company.
Get the Book