ARR and growth rate: the baseline
Annual Recurring Revenue and its month-over-month or year-over-year growth rate are the first numbers Series A investors look for. Show both the absolute number and the trajectory. A company at $800K ARR growing 15% MoM is a very different proposition from one at $1.2M ARR growing 3% MoM. The growth rate matters as much as the number — sometimes more. Benchmark: most top-tier Series A investors expect $1M–$3M ARR with strong growth for B2B SaaS.
NRR: the metric that proves the product works
Net Revenue Retention tells investors whether existing customers are expanding, contracting or churning. NRR above 100% means your revenue base grows even without new customer acquisition — which is the single most powerful signal in B2B SaaS. NRR below 80% is a serious concern at Series A. Present NRR on the Traction or Business Model slide with a one-sentence explanation of what drives it (expansion revenue, upsell, seat growth).
CAC and LTV: the unit economics pair
Customer Acquisition Cost and Lifetime Value are the inputs to the most fundamental SaaS ratio. LTV:CAC of 3:1 or higher is the standard benchmark for a healthy Series A business. Show both numbers, show the ratio, and show how CAC has trended as you've scaled (ideally: decreasing as channels become more efficient). Investors who can't find these numbers in your deck will ask for them in the first meeting — have them ready on a slide.
Payback period: the cash efficiency signal
CAC payback period — the number of months until a customer has paid back their acquisition cost — shows how capital-efficient your growth is. Under 12 months is strong. 18–24 months is acceptable at Series A with high NRR. Over 24 months requires a specific narrative (enterprise contracts, high LTV, land-and-expand). Present this alongside CAC/LTV. Investors are assessing how much capital you'll need to sustain growth — payback period is the answer.
Rule of 40 and what it signals
The Rule of 40 (revenue growth rate + profit margin ≥ 40%) is a heuristic for growth-stage companies, less commonly used at early Series A. But if your growth rate is slowing, a high margin can compensate. If your margins are thin, growth needs to be exceptional. Knowing where you stand on Rule of 40 — and being able to explain it — shows financial maturity that differentiates you in partner meetings.