SaaS economics, in five lessons

MRR or ARR describes recurring revenue; churn measures losses; CAC measures acquisition cost; LTV estimates lifetime gross profit; ROI and payback assess investment returns. Review these with margin and cash flow. Signups and downloads can also be useful when connected to later customer behavior.

Choose a cadence that fits the data and decision. Monthly reviews are a useful starting point for recurring revenue, churn, and CAC, with shorter monitoring for unusual changes. Update LTV when its revenue, margin, or retention assumptions change. Review ROI forecasts against actual outcomes over the planned horizon.

SaaS metrics add subscription and customer-cohort views to financial reporting. MRR is a normalized current subscription run rate; LTV estimates value over a customer relationship; CAC payback estimates acquisition-cost recovery from gross profit. They complement cash-flow and accounting measures rather than replacing them.

Bessemer uses 3:1 as an LTV:CAC operating target. It is a reference, not proof of viable growth. Below 1:1, modeled lifetime gross profit does not cover acquisition cost; even above 3:1, payback, overhead, concentration, and cash needs matter. A ratio above 5:1 does not automatically mean you should increase spend. Source: https://www.bvp.com/atlas/scaling-to-100-million

MRR expresses active subscription revenue on a monthly basis, including annual subscriptions normalized to a month. In this calculator ARR = MRR × 12. Multiplying by 12 does not smooth changes or forecast future revenue; it expresses the same run rate annually.

The definitions stay the same, but interpretation can change with scale. A small customer base makes rates sensitive to individual accounts, so review absolute counts and customer details. Larger bases can support more segmentation. Use the metrics relevant to the decision rather than a fixed early-stage or growth-stage checklist.