The SaaS Metrics Glossary: MRR, ARR, NRR, CAC, LTV, Payback (2026)

TL;DR. SaaS businesses run on a small set of interlocking metrics: MRR/ARR (revenue scale), NRR/GRR (revenue durability), churn (leakage), CAC and payback (cost of growth), LTV:CAC (unit economics), burn multiple (capital efficiency), and Rule of 40 (growth-profit balance). This glossary defines each one, gives the formula, and states benchmarks by stage — because a "good" number at $1M ARR is a warning sign at $20M.

Revenue metrics

MRR (Monthly Recurring Revenue)

MRR is the normalized monthly value of all active subscriptions. Annual contracts divide by 12; one-time fees, services, and overage charges are excluded.

MRR moves through four channels, and reporting them separately is what makes MRR useful:

• New MRR — from new customers
• Expansion MRR — upgrades, seats, cross-sell to existing customers
• Contraction MRR — downgrades
• Churned MRR — cancellations

Net New MRR = New + Expansion − Contraction − Churned

ARR (Annual Recurring Revenue)

ARR = MRR × 12. Used for scale conversations ($1M ARR, $10M ARR milestones). The trap: counting non-recurring revenue (services, one-time setup) in ARR. Investors will strip it out in diligence; better to report it clean yourself.

Retention metrics

GRR (Gross Revenue Retention)

GRR measures how much recurring revenue you keep from an existing cohort, ignoring expansion. Formula: (starting MRR − churn − contraction) / starting MRR, over 12 months. Ceiling is 100%.

Benchmarks: 90%+ is healthy for SMB products, 95%+ for enterprise. GRR below 80% means the product is leaking faster than most GTM motions can refill.

NRR (Net Revenue Retention)

NRR is GRR plus expansion — how much a cohort's revenue grows even with zero new logos. Formula: (starting MRR − churn − contraction + expansion) / starting MRR.

Stage / segment	Healthy NRR
SMB-focused SaaS	95–105%
Mid-market	105–115%
Enterprise	110–130%

NRR above 100% means the business grows without new sales — the single strongest predictor of durable SaaS value. Public-market leaders (Snowflake, Datadog in their growth years) ran 130%+.

Churn

Logo churn = % of customers lost per period. Revenue churn = % of MRR lost. They diverge whenever customers differ in size — losing 10 tiny accounts can matter less than one enterprise contraction. Always state which churn you mean and over what period; a "2% churn" that's monthly is ~22% annually.

Acquisition metrics

CAC (Customer Acquisition Cost)

CAC = total sales + marketing spend / new customers acquired in the period. Include salaries, tools, and program spend — not just ad budget. A "blended CAC" mixes paid and organic; report paid CAC separately or the blend hides deteriorating paid efficiency behind organic growth.

CAC Payback Period

Payback = CAC / (monthly recurring gross profit per customer). Note gross profit, not revenue — divide by gross margin.

Motion	Healthy payback
Self-serve / PLG	under 12 months
Mid-market sales-led	12–18 months
Enterprise	18–24 months

Payback is the most operationally honest acquisition metric: unlike LTV, it uses no forward-looking assumptions. See Product-Led Growth for how PLG motions compress it.

LTV (Customer Lifetime Value) and LTV:CAC

LTV = average monthly gross profit per customer × average customer lifetime in months, where lifetime ≈ 1 / monthly churn rate. The classic health bar is LTV:CAC ≥ 3.

Handle with care: at low churn rates the formula extrapolates decades of retention from months of data. Early-stage companies should lean on payback and NRR; LTV becomes trustworthy once cohorts are 2+ years old.

Efficiency metrics

Burn Multiple

Burn multiple = net burn / net new ARR. How many dollars you burn to add a dollar of ARR. Under 1x is excellent, 1–1.5x good, 2x+ concerning past Series A. It's the metric that catches "growth at any cost" — a company can show strong ARR growth while the burn multiple quietly reveals the growth is bought, not earned.

Rule of 40

Revenue growth rate % + profit margin % ≥ 40. A 60%-growth company can burn 20% margins; a 10%-growth company must run 30% profitable. Below ~$10M ARR the rule is noisy; it becomes a real gate in growth and late stage.

Magic Number

Net new ARR in a quarter × 4 / sales & marketing spend of the prior quarter. Above 0.75, sales efficiency supports increased investment; below 0.5, fix the funnel — see ICP definition — before adding spend.

Which metrics matter at which stage?

• Pre-PMF (under $1M ARR): activation, retention cohorts, logo churn. Ignore LTV. Watch product-market fit signals.
• $1–10M ARR: NRR, CAC payback, burn multiple. This is where unit economics get set.
• $10M+ ARR: NRR, Rule of 40, magic number, paid vs. blended CAC. Efficiency now prices the company.

Related reading

• All SaaS metrics articles — the growing cluster.
• The Complete Guide to OKRs for SaaS Teams — turning these metrics into quarterly goals.
• Need a metrics deep-dive for your board deck? Talk to us.