Subscription Business Metrics: The Complete Glossary

New to a SaaS finance or growth role and drowning in acronyms? This is a reference, not a tutorial: short definitions and formulas for the subscription business metrics you'll see in board decks, investor updates, and dashboards, each linked to a full walkthrough if you need the worked example, the common mistakes, or the step-by-step calculation.

If you're looking for a process to decide which metrics to review each month and how to run that review, SaaS financial metrics: a practical how-to guide covers that operating side. This page is the glossary you keep open in a second tab.

Table of Contents

• Revenue Metrics
• Retention Metrics
• Unit Economics
• Growth and Engagement Metrics
• How to Use This Glossary Without Getting Lost
• FAQ: Subscription Business Metrics
• Conclusion

Revenue Metrics

MRR (Monthly Recurring Revenue) — the normalized monthly value of active subscriptions. An annual contract counts at 1/12th its value per month, not as a lump sum in the month it's paid. How to calculate MRR walks through a full worked example.

ARR (Annual Recurring Revenue) — MRR annualized, generally MRR × 12. Used for board updates and company-scale conversations rather than month-to-month operating review. Annual recurring revenue calculation covers where ARR and MRR diverge on contract-based pricing.

ARPU / ARPA (Average Revenue Per User / Account) — MRR divided by active paying customers or accounts. Tells you whether revenue growth is coming from more customers or from each customer paying more. See the ARPU formula guide.

Bookings vs. billings vs. revenue — three different numbers that often get conflated: bookings is the contract value agreed at signing, billings is what's actually invoiced, and revenue is what's recognized as earned. Bookings vs. billings vs. revenue breaks down when each one matters.

Retention Metrics

Customer churn rate — the share of customers lost during a period, divided by customers at the start of the period. Revenue churn measures lost recurring revenue instead of lost accounts, and the two numbers can tell very different stories. How to reduce customer churn and logo churn vs. revenue churn dig into why you need both.

GRR (Gross Revenue Retention) — starting recurring revenue kept after churn and contraction, excluding any expansion. GRR can't exceed 100%, which makes it a clean check on churn independent of upsells.

NRR (Net Revenue Retention) — GRR plus expansion revenue from upgrades and added seats. NRR can rise above 100% when expansion outweighs losses. The net revenue retention formula guide has the full calculation; what counts as a good NRR covers how to read the result against your stage and segment.

Expansion revenue — the added recurring revenue from customers who were already paying, via upgrades, added seats, or usage growth. It's the input that separates NRR from GRR. See expansion revenue: definition, formula, and examples.

Unit Economics

CAC (Customer Acquisition Cost) — total sales and marketing spend divided by new paying customers acquired in the same period. How to calculate customer acquisition cost covers what to include and exclude.

LTV (Customer Lifetime Value) — the recurring gross profit a customer is expected to generate over their relationship with your product, commonly estimated as ARPU × gross margin ÷ churn rate. How to calculate LTV for SaaS has the full method; customer lifetime value formula covers the ecommerce and marketplace variants.

CAC payback period — how many months of gross profit from a customer it takes to recover the cost of acquiring them. A useful cash-timing check even when your LTV:CAC ratio looks healthy.

LTV:CAC ratio — LTV divided by CAC, a rough measure of whether acquisition spend is paying off. A commonly cited planning reference is 3:1 or higher, though the right number depends heavily on gross margin and payback time.

Growth and Engagement Metrics

Trial-to-paid conversion rate — the share of trial signups who become paying customers within a defined window. See the trial to paid conversion rate guide for benchmarks and how to read them by trial type.

Net negative churn — a state where expansion revenue from existing customers exceeds revenue lost to churn and contraction, meaning your existing base grows even with zero new sales. Effectively NRR sustained above 100%. Net negative churn math covers the mechanics.

Rule of 40 — growth rate plus profit margin, used as a rough health check that trades growth against profitability. What is the Rule of 40? covers where it's useful and where it breaks down.

SaaS Magic Number — a rough measure of sales efficiency, comparing quarter-over-quarter revenue growth against the prior quarter's sales and marketing spend. See SaaS burn multiple for a related capital-efficiency metric.

How to Use This Glossary Without Getting Lost

Don't try to track every metric on this page at once. Most SaaS teams operate well with five to seven numbers reviewed regularly, plus a couple more pulled in only when something looks off.

A workable starting set: MRR (are we growing), customer and revenue churn (are we keeping customers), NRR (is the existing base expanding or shrinking), and CAC with LTV (is new growth worth what it costs). Add trial-to-paid conversion if you run a self-serve funnel, and Rule of 40 or the Magic Number once you're reporting to a board or investors.

Chartsy calculates most of these directly from Stripe or Paddle billing data, so you're not maintaining the formulas in a spreadsheet by hand.

FAQ: Subscription Business Metrics

What's the difference between MRR and ARR?

MRR is normalized monthly recurring revenue; ARR is that figure annualized, typically MRR × 12. Use MRR for operating reviews and ARR for annual planning and board-level scale conversations.

What's the difference between GRR and NRR?

GRR excludes expansion revenue and can't exceed 100%. NRR includes expansion and can exceed 100% when upgrades outweigh churn and contraction. Track both — NRR alone can look healthy while GRR reveals a real churn problem underneath it.

Do I need to track all of these metrics?

No. Most early-stage SaaS teams need five to seven core metrics reviewed consistently, not a dashboard with every term on this page. Start with revenue, churn, and NRR, then add unit economics once you have enough acquisition volume to make CAC and LTV meaningful.

Where do I find the formula for a specific metric?

Each entry above links to a dedicated guide with the full formula, a worked example, and common calculation mistakes for that metric specifically.

Conclusion

Use this page as a lookup, not a checklist to fill in all at once. When a term comes up in a board meeting or a metrics dashboard, find it here for the plain-English definition, then follow the link if you need to actually calculate it from your own billing data. If your subscription data lives in Stripe or Paddle, Chartsy can calculate most of these metrics directly and answer follow-up questions in plain English.