ARR, net revenue retention, LTV:CAC ratio, gross margins. At Series A, the numbers need to tell a compelling story on their own.
At Series A, the standard changes. Investors aren't evaluating potential anymore — they're evaluating performance. Your metrics need to be strong enough to speak for themselves, specific enough to be defensible, and honest enough to hold up under scrutiny. A strong metrics story is what separates a fundable Series A from a company that needs more time.
ARR (Annual Recurring Revenue) — your annualised recurring revenue base. The minimum ARR to raise a Series A varies, but £1–3m ARR is a common range in the UK market. More important than the number is the growth rate — typically 2–3x year-on-year for a Series A raise.
ARR thresholds shift with market conditions — treat these as directional benchmarks and confirm against current investor data before relying on them.
Net Revenue Retention (NRR) — the percentage of revenue you keep and grow from existing customers after accounting for churn, downgrades, and expansions. Above 100% NRR means your existing customer base is growing even without new customers — a powerful signal. Best-in-class SaaS companies run 120%+. Below 85% is a concern. 8/10 certainty — broadly consistent across sources.
LTV:CAC ratio — at Series A the ratio should be 3:1 or better, and your payback period should be under 18 months. Investors will want to see this holding as you've scaled acquisition, not just at ten customers. See the unit economics guide for detail on the calculation.
Gross margin — how much of each pound of revenue you keep after direct costs. For software businesses, 60–80% is the expected range. Below 50% and investors start asking hard questions about whether the business is truly a software company or a services company in disguise. 8/10 certainty.
Defensible means you can explain where every number comes from, how it's calculated, and what assumptions sit behind it. An investor who asks "how do you calculate NRR?" should get a clean, immediate answer with a methodology they can verify. Metrics that fall apart under ten minutes of questioning are worse than having no metrics at all.
Including non-recurring revenue in ARR. Using revenue recognised before cash is collected. Calculating churn on a customer basis when the pound basis tells a worse story — or vice versa. Using a short measurement window that flatters the number. Investors have seen all of these. Be consistent in your methodology and document it.
What good looks like: A founder who walks into a Series A meeting with a one-page metrics summary — ARR, growth rate, NRR, gross margin, LTV:CAC — with clean definitions, consistent methodology, and month-by-month data behind each number available on request. The metrics tell the story before the founder says a word.
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Try the funding finder →This is general information, not financial or legal advice. Always do your own research and seek independent professional advice.