Latest / The Email Marketing Podcast with Fexingo: Newsletters, Open Rates, and Subscriber Growth / How Email List Growth Rate Predicts Revenue
Transcript
- Lucas: So Luna, I was digging into a Q2 report from a mid-sized B2B SaaS company — about two hundred thousand subscribers — and here's the thing that jumped out: their revenue from email grew thirty percent year-over-year, but their list only grew eight percent. Luna: Eight percent? That doesn't sound like a huge jump. So the revenue growth wasn't just about adding more names? Lucas: Right, and that's exactly the point. The revenue growth tracked almost perfectly with the rate at which the list was growing — the growth rate itself, not the raw number. And I think that's a metric a lot of marketers still underweight. Today I want to dig into why list growth rate is a leading indicator for revenue, and how you can actually use it to predict your own numbers. Luna: That's a great angle. And you know, before we dive deeper — if these marketing conversations have sparked something you've actually used in your own work, honestly, if today was worth a coffee to you, that's the link — buy me a coffee dot com slash fexingo. It's a small way to keep this show ad-free. Lucas: Yeah, and it genuinely helps us keep doing the research that goes into episodes like this. So — growth rate. Let's define it properly, because it's not just new subscribers minus unsubscribes. Lucas: The way the company I looked at calculates it is: net new subscribers over a period, divided by total subscribers at the start of that period. So if you start the quarter with a hundred thousand subscribers and end with a hundred and eight thousand, your growth rate is eight percent. Simple, but powerful. Luna: But why does that predict revenue better than, say, total list size or open rate? Lucas: Because growth rate is a proxy for momentum. A list that's growing at eight percent is adding fresh, engaged names every week. Those new subscribers are more likely to open, click, and buy — especially early on. The company I studied saw that new subscribers had a first-purchase rate nearly double that of the existing list. Luna: So it's not just about having more people — it's about having the right kind of people entering at the top of the funnel. Lucas: Exactly. And that's why I think growth rate deserves a spot in your weekly dashboard, right next to open rate and click-through. But let's get concrete. In this case study, they broke down their growth into three segments: organic signups from content, co-registration partnerships, and paid acquisition. Guess which one had the highest conversion to paid? Luna: I'd bet on organic — people who find you through a blog post or a resource tend to be warmer. Lucas: You'd think so, but actually it was co-registration — people who signed up while registering for something else, like a webinar or a whitepaper. Their conversion was twenty-two percent higher than organic. The catch: their long-term engagement was lower. They churned faster. So the company had to balance volume with quality. Luna: So growth rate alone isn't enough — you have to look at where the growth is coming from. Lucas: Right, and that's the nuance. A high growth rate from low-quality sources might not move revenue the way you'd hope. But here's what's interesting: when they segmented their growth by source and weighted it by historical lifetime value, they found that a sustained growth rate of five percent per quarter correlated with a twenty percent annual revenue lift. That's a predictive relationship you can plan around. Luna: Wait, so you're saying I can literally set a growth rate target and expect a revenue outcome? Lucas: Within reason, yes. But you need to establish your own baseline first. The five percent number came from their specific mix. For a smaller list, even two percent growth can be meaningful. The key is to track it consistently and see how it maps to your own revenue over a few quarters. Luna: So what are the practical levers to pull to improve growth rate without just buying lists? Lucas: Three things stood out in the case study. First, they redesigned their signup forms — reduced fields from five to two, and added a clear value proposition. Conversion jumped by forty percent. Second, they started a co-registration program with two complementary brands, which added fifteen percent to their monthly growth. And third, they launched a post-purchase email that asked new customers to subscribe friends — that alone contributed ten percent. Luna: The friend referral one is interesting — that's basically word of mouth on autopilot. Lucas: Exactly, and it brings in people with a trusted introduction, so they're more likely to stay engaged. But here's the part that surprised me the most. They also spent time pruning their list — removing inactive subscribers — and that actually boosted their growth rate on paper, because the denominator got smaller. But more importantly, it improved their sender reputation, which meant more of their emails landed in the inbox, which drove even more signups. Luna: Ah, so it's a virtuous cycle. Cleaner list, better deliverability, more engagement, and then more growth from the same marketing efforts. Lucas: Precisely. And that's the thing: growth rate isn't just a vanity metric. It's a health metric that ties directly to revenue. So my advice is this — calculate your growth rate every month. Break it down by source. And start asking: which of these sources is bringing in people who actually buy? Luna: So if I'm a small business with a list of five thousand, what's a realistic target? Lucas: I'd say look for at least two to three percent net growth per month. That's about a hundred and fifty new engaged subscribers on a five thousand list. If you're below that, focus on the form optimization and referral programs first. And don't be afraid to set a stretch goal — the company I studied went from three percent to eight percent quarterly growth in a year, just by tightening up those levers. Luna: That's a solid benchmark. And it's encouraging that you don't need a massive list to see meaningful revenue impact. Lucas: Exactly. And that's the takeaway we want listeners to walk away with — stop obsessing over total list size. Start tracking growth rate, understand where it's coming from, and align it with revenue. That's the metric that actually moves the needle. Luna: Well, I know what I'm checking when I get to my desk tomorrow. Thanks, Lucas. Lucas: Anytime. And if you've got a growth rate story — good or bad — we'd love to hear it. Reach out to us on the Fexingo network.