SaaS metrics explained: the complete guide
SaaS metrics fall into five stages of one funnel: acquisition (what a customer costs), revenue (what they pay), margin (what you keep), retention (how long they stay), and efficiency (whether cash turns into durable revenue). Master one metric per stage and you can read almost any SaaS business.
How the metrics connect
They are not a list — they are a chain. Traffic converts at a conversion rate into customers, each bought at a CAC. Those customers pay, producing MRR / ARR and an ARPU. After gross margin and churn, ARPU becomes lifetime value. The single equation that ties the chain together:
LTV = (ARPU × Gross Margin) / Churn rate LTV : CAC ≥ 3 : 1 → healthy unit economics CAC Payback = CAC / (ARPU × Gross Margin)
Above the line, the business model works. Whether it survives is a cash question: burn rate sets the speed, runway the distance left, and burn multiple the efficiency of turning that cash into new ARR. A company is durable when its unit economics are healthy and its burn multiple is low.
1. Acquisition — getting users in
How efficiently you turn attention into customers, and what each one costs.
- Conversion rate — Percentage who take the desired action — the funnel’s core efficiency metric.
- Customer Acquisition Cost (CAC) — Total sales + marketing spend divided by new customers won.
- CAC vs CPA — Cost per paying customer vs cost per action — different denominators.
- Visitors → customers — The end-to-end funnel conversion math from traffic to paying users.
- Leads → customers — Lead-to-customer conversion rate for sales-led funnels.
2. Revenue — what they pay
The recurring-revenue metrics that define a subscription business.
- MRR — Predictable subscription revenue normalized to one month.
- ARR — Recurring revenue normalized to a year (MRR × 12).
- ARPU — Average revenue per user — the top input to LTV.
- MRR vs ARR — Monthly vs annual framing of the same recurring revenue.
3. Margins — what you keep
The cascade from delivery cost to bottom line. Gross margin is the ceiling on everything else.
- Gross margin — Revenue minus COGS — product/delivery efficiency; the ceiling on every metric below.
- Net margin — Profit after ALL costs — the true bottom line.
- Contribution margin — Revenue minus variable costs — drives break-even and pricing.
- Gross vs net margin — The full margin cascade from delivery cost to bottom line.
4. Retention — keeping them
Retention is the multiplier on every acquired customer — and the denominator of LTV.
- Churn rate — Percentage of customers (or revenue) lost in a period — the LTV killer.
- Net Promoter Score (NPS) — Likelihood-to-recommend score — a leading retention signal.
- Churn vs retention — Two sides of the same coin: churn + retention = 100%.
- NPS vs CSAT — Loyalty (relationship) vs satisfaction (transaction) measures.
5. Efficiency & cash — sustainable growth
Whether the whole machine converts cash into durable, profitable revenue.
- Lifetime Value (LTV) — Total margin a customer delivers over their lifetime: ARPU × margin ÷ churn.
- LTV:CAC ratio — The canonical unit-economics health check — 3:1 is the threshold.
- Burn rate — How fast cash is spent; net burn is the survival number.
- Runway — Months of life left: cash ÷ net burn.
- Burn multiple — Net burn ÷ net new ARR — the cleanest growth-efficiency measure.
- Burn vs runway — Speed of spend vs distance remaining.
- Product-market fit (PMF) — The point where the market pulls the product — prerequisite to scaling spend.
Where to start
If you read only three: LTV:CAC (is acquisition profitable?), churn (does the revenue stay?), and burn multiple (is growth efficient?). Those three answer most questions about a SaaS business’s health.
Each metric links to a full explainer with formula, benchmarks, and worked examples. This guide is reference, not financial or investment advice.