In 2025, every campaign you send either trains inboxes to trust you more… or trust you less – and the only way to know is to track your metrics
Most email marketers don’t have a deliverability problem… they have a tracking problem.
They’re either watching the wrong metrics, watching them too late, or not watching them at all. And in 2025, that’s how you end up with campaigns that don’t convert, emails that go to spam, and lists that quietly die in the background while you keep wondering why sales dipped.
In the old days, email marketing success felt kind of… intuitive. You’d write a clever subject line, hit “send,” cross your fingers, and hope the sales came rolling in. If the open rate seemed decent, great. If not? You shrugged it off and tried again next week.
But that version of email marketing is long gone.
In 2025, our inboxes are smarter, spam filters are harsher, and privacy regulations have changed how performance gets tracked. AI tools now decide whether your emails deserve the inbox or the Promotions tab, sometimes without even “reading” your message. Apple and Gmail no longer reliably report opens for everyone. And sending emails based on “what feels right” is a fast track to burning your domain reputation.
Now, the thing is instinct still has its place but data is how you scale, adapt, and win in a crowded, competitive inbox environment.
Think about it… if you don’t know your average bounce rate, if you aren’t tracking engagement decay, if you can’t see what subject lines convert clicks into real business outcomes… then you cannot optimize based on data, you’ll only be guessing. And marketers who treat metrics like a second thought usually find themselves frustrated, their emails throttled, or worse – blacklisted.
In this blog, we’re going to walk you through the 8 core email metrics that reveal the real health of your campaigns and can make or break your deliverability, engagement, and revenue. So grab your favorite drink, open up your campaign dashboard, and get ready.. Because once you start measuring what matters, everything about your email marketing changes – for the better. Understanding these metrics is how you 10X your ROI.
The 8 key metrics you need to track in 2025.
So as we mentioned earlier the rules have changed, yes. But that doesn’t mean email is dead. In fact, it’s more powerful than ever if you know how to play by the new rules. And the first step to doing that is understanding what metrics actually matter now. Because when you know what to track, you can actually start improving. Let’s get into it.
1. Bounce Rate
Your bounce rate is a metric, but it’s also a direct reflection of your list quality, data hygiene, and sender reputation. In 2025, inbox providers like Gmail and Outlook are placing more weight on bounce patterns when evaluating whether your next email deserves the inbox or the spam folder.
Now, there are two types of bounces: hard bounces and soft bounces. Hard bounces mean the email address is invalid, fake, or permanently unreachable. Soft bounces are temporary issues like a full inbox or a down server. But it’s 2025 and today, too many soft bounces make ISPs and ESPs look at you as a sender who may be losing control of their hygiene and you could get penalized.
A healthy bounce rate should be under 2% and in some cases under 0.7% has become the new benchmark, especially in B2B campaigns where businesses get new domains churn fast and layoffs or role changes cause addresses to go stale overnight. If yours clocks in at above that, it’s time to act. Audit your list source, clean up inactive or unengaged contacts, and double-check for any recent imports from unverified sources.
In our experience here at Abervin Digital, the solution isn’t just about avoiding bad emails. It’s about building systems that prevent bad emails from ever entering your list in the first place. One way to make sure your bounce rate is low is to make sure you are only sending messages to triple verified lists, using double opt-in during sign-ups and in fact, the best strategy in 2025 is to automate bounce-handling rules inside your ESP. For example:
- Suppress a contact after 1 hard bounce.
- Suppress after 3 consecutive soft bounces.
Creating filters or flows based on this logic allows you to quietly remove the risky profiles before they hurt your engagement ratio. What too many marketers underestimate is that bounce rates don’t just reflect on one campaign – they compound over time. If you ignore this metric, it doesn’t just hurt your engagement. It actively cripples your domain reputation, suppresses inbox placement, and puts your entire email program at risk.
2. Open Rate
Open rate used to be all you needed to see to know if things were working. If it was high, you’re on the right track and if it dipped, something was broken. Until Apple Mail Privacy Protection (AMPP) threw a wrench in the gears by auto-opening emails in the background so your email gets marked “read” even if no one actually reads it thanks to automatic prefetching. You could be celebrating a 42% open rate when, in reality, a third of those were ghost opens from iOS devices doing background email scans.
So in 2025, what does the open rate metric actually tell us?
Open rate is still useful, just not on its own. Instead of freaking out over whether your open rate is “accurate,”, think about what direction it’s pointing in. Think of your open rate now like a check engine light: it won’t tell you exactly what’s wrong, but it tells you something is. If you suddenly dip from a steady 30% to 18%, that’s not Apple – that’s something you need to investigate. If your open rate drops dramatically, it could mean subject lines are stale, your sender name lacks trust, or your emails are getting filtered to junk.
One way to read open rates accurately in 2025 is to monitor opens by domain. Your ESP may be able to show you which opens are coming from Apple Mail or Gmail so you can group your data accordingly. If Gmail open rates are solid but Yahoo or Outlook is tanking, that’s a red flag about your deliverability to specific ISPs. You can also use inbox placement tools (like GlockApps or Mail-Tester) to get the full picture of what’s going on with your open rates.
The trick in 2025 with Open Rates is “Clicks” are the new opens. If you’re segmenting based on engagement – pruning lists, warming IPs, building retargeting audiences – do it based on clickers, not just openers. Clicks are definitive. No algorithm fakes them. No privacy feature inflates them. Someone saw your content, made a decision, and took action. That’s the real win.
Open rates might not be as trustworthy in 2025, but when interpreted right especially when you consider clicks, bounces, and inbox placement, they still help you stay one step ahead of the game.
3. Click-Through Rate (CTR)
Click-through rate is your content check engine light. It tells you whether your email actually moved someone to act. Opens used to be enough, but not anymore. In 2025, CTR is more valuable than ever because it reflects engagement after the open – something providers can’t fake.
A strong CTR typically sits between 2–5%, but this varies by industry. But honestly, these global averages matter less than your own reports. Are your clicks going up over time? Or did they spike in Q1 and quietly die off while you weren’t looking?
When CTR tanks, it’s rarely ever one thing. Sometimes the content’s too dense. Sometimes you buried the CTA in paragraph four. Other times it’s design: too many links, too many choices, too many moments where the customers goes “Huh?”.
Every time your email has 10 links and 3 different calls-to-action, you didn’t give the reader options – you gave them a decision tree. And in 2025’s overloaded inboxes and short attention spans, might as well kiss your conversions goodbye.
So here are some things we recommend for the best CTR performance per campaign. Start by focusing on one goal per email. One action you want the reader to take. Use buttons that are big, bold, tappable on mobile to highlight this action. Your CTAs should feel written by humans, not AI. A CTA button that clearly says “Get the free checklist” will always beat “Click here to learn more.”
Now, in 2025, when you get that click, you don’t just want to know who clicked, you want to know when. If most of your clicks come in the first 3 minutes, your subject line and preheader did their job. If people are clicking 12, 24, 48 hours later, that might signal they saved your email for later or that your message only hit when their inbox was quiet. Both are clues that can shape your future send strategies.
Smart ESPs now let you segment by click velocity. Use that data. Build follow-ups that match that behavior targeting fast-clickers who might be ready for offers. Late-clickers, on the other hand, might need more information and a few more nudges to take action.
In the end, CTR is the engagement metric that decides your inbox fate.
4. Click-to-Open Rate (CTOR)
Click-to-Open Rate is the metric that shows how many of your actual openers clicked. It calculates how many of your openers found your content compelling enough to act. It follows a basic math: (Clicks ÷ Opens) × 100
Let’s say you run a campaign and get a 28% open rate and a 2.8% click rate. That’s a 10% CTOR – and in many verticals, that’s fine. But let’s say your campaign was a limited-time promo, pushing a new feature, or sending a highly targeted sales message, that 10% might actually mean your openers are disconnecting from the offer. Maybe your subject line overpromised. Maybe your CTA got buried. Maybe your offer didn’t match your segmentation.
In 2025, smart email marketers know that fewer clicks today mean fewer opens tomorrow so they study the CTOR metric to:
- Diagnose content mismatch (Did the email promise something the body didn’t deliver?).
- Test different hero images or text headlines.
- Refine CTA placement and copy.
So what’s a “good” CTOR? Context matters. For educational newsletters, 8–12% might be solid. For product announcements or ecommerce flash sales, you should aim for 15%+. Anything north of 20% and you’re breathing rarified air – and that usually only happens with laser-sharp targeting, great storytelling, and CTAs that feel inevitable.
Bottom line is this: your CTOR is the truth about how your email outreach is really performing.
5. Unsubscribe Rate
In 2025, inbox providers are not just watching who unsubscribed, they’re watching how many did, and how often. So a sudden spike in unsubscribes doesn’t just trim your list, it dents your sender reputation in subtle, compounding ways.
A healthy unsubscribe rate today hovers under 0.2% for engaged lists, with anything over 0.5% raising deliverability eyebrows. But it’s not just the number – it’s the pattern. Gmail, Outlook, and Apple Mail don’t just tally unsubscribes. They factor in context: was this a promotional blast or a nurture email? Was it sent to new leads or long-time subscribers? Did the person open and scroll – or click out within seconds? Inboxes providers are not waiting for angry spam complaints. If too many people silently opt-out, it is enough to start throttling your inbox placement.
Now the tricky thing is that unsubscribes can look like a hygiene win. You think “They’re cleaning themselves out – that’s good, right?” Sometimes, yes. Especially if you’re sending at scale. But when those unsubscribes come from the wrong segment, for example, new subscribers, or reactivated leads – it means your first impression sucked. Or worse, that your content was confusing.
The good news is smart ESPs in 2025 now offer unsubscribe heatmaps – visual breakdowns of who left, when, and what they saw before leaving. Use that data. If unsubscribes spike on a promo-heavy week, segment more tightly. If they rise after a lead magnet follow-up, rethink your onboarding. Maybe your welcome emails are overhyped and underdelivering. Maybe your list source is cold and low-intent.
Either way, your list is talking to you via your unsubscribe rate and it is your job is to listen before the platforms do.
6. Spam Complaint Rate
A bounce let’s you know there’s an error, unsubscribes let you know they’re leaving but a spam complaint? That’s a silent vote against your credibility, quietly reported to mailbox providers like Gmail, Outlook, and Yahoo. And these guys absolutely keep score.
Once upon a time, you could get a 0.2% or even 0.3% spam complaint rate and be okay. Today? Even 0.1% , that is one complaint per 1,000 emails can trigger filters, suppression, or a slow-but-steady decline to where your emails are sent straight into spam folder. In 2025, one bad campaign or worse, one bad segment can hurt your email marketing without warning.
The irony is many of the senders getting flagged aren’t even spammers. They’re brands with real lists, real content, and real intentions. But they forget that user tolerance has changed. With so many businesses vying for the same attention, users are quick to swipe or click. And thanks to modern UX, every email client now features a prominent “Report Spam” button which is usually easier to find than the actual unsubscribe link.
So how do you keep spam complaint rate low? Well, it starts before the send – using Double opt-in is step #1.
If you’re still running single opt-in in 2025, you’re playing with fire. Typos, bots, and throwaway accounts that never meant to engage with you in the first place will come back as spam complaints months down the line. And inbox providers won’t care about your intent – only your footprint.
Second, context is everything. Don’t assume your audience remembers how they landed on your list. A simple line near the top that says “You signed up for product updates from [brand]” can dramatically reduce knee-jerk complaints. People are more forgiving when they remember giving permission.
Third, bring the exit closer. Yes, really. Putting the unsubscribe link above the fold, especially in longer emails, can actually reduce spam complaints. When users feel trapped or have to scroll to escape, they reach for the nuke button. Let them go gracefully, and your reputation lives to see another day.
The good news is modern ESPs and inbox providers now allow you to automatically suppress anyone who marks your email as spam. It’s called complaint-based suppression, and if your platform supports it, turn it on immediately. You won’t win them back anyway but keeping them on your list just poisons your future sends.
Watch this metric like a hawk. It’s not the loudest, but it’s the most dangerous. If you ever see a spike – even a fraction of a percent above normal – stop. Not slow down. Not adjust copy. Stop. Investigate your audience, your message, your recent list imports. Whatever campaign you had queued up next can wait. Because once you lose inbox placement, there is no quick reset button. Reputation is earned slowly, and it dies fast.
7. Conversion Rate
This is the metric that answers the: Did this campaign work? question.
Conversion rate is what tells you if your email campaign with the clever copy or beautiful design is worth anything. It measures how many people not only opened and clicked, but also how many crossed the finish line. Whether it is signing up, buying something, booking a demo or replying to your message – whatever success means to your campaign, this is the metric that puts numbers to it.
But in 2025, conversion tracking isn’t plug-and-play. The privacy changes of the last few years, from Apple’s Mail Privacy Protection to tightening cookie rules and the full phasing out of third-party tracking have forced marketers to rebuild their attribution playbook from scratch. You can’t just drop a Facebook Pixel and hope for clarity anymore. Now it’s about precision: first-party data, UTM tagging discipline, server-side tracking, and clean event configuration inside platforms like GA4 or Mixpanel.
This is very important because the best open and click rates in the world mean very little if they don’t drive meaningful action. So if your numbers look good at the top of the funnel but conversions are flat, the culprit is almost always post-click friction.
What happens after they land matters more than ever. If the email offers a “free trial,” but the landing page leads with a pricing table, people bounce. If the CTA says “book a call,” but the booking form is clunky, has five extra fields, and loads like it’s stuck in 2009, people dropoff. And if there’s no trust built when they arrive, so let’s say you have no testimonial, no benefit clarity, no instant relevance, people are less likely to convert, no matter how warm the traffic.
Conversion is often a byproduct of the entire ecosystem working well: email, landing page, product value, and timing. It’s not just how many people you reached, it’s how many believed you, trusted you, and took action because of your entire ecosystem.
8. List Growth Rate
So this is something very few marketers EVER pay attention fall into the trap of obsessing over how their list is performing open rates, click-throughs, conversions. But fewer stop to ask the more foundational question: is the list growing in a way that actually matters?
In 2025, when inbox providers are evaluating not just engagement, but the velocity and quality of subscriber acquisition, your List Growth Rate has to show your brand’s forward momentum and inbox worthiness. Put simply, inbox providers want you to keep growing… or else.
To calculate your list growth rate the formula is: (New Subscribers – Unsubscribes) ÷ Total Subscribers × 100.
Now, if your list is growing fast but filled with low-intent, unengaged users, the kind who never open, never click, and silently ignore your messages, you’re not just bloating your ESP bill, you’re dragging down your deliverability score across the board.
ISPs don’t care that you added 10,000 names. They care that 9,800 of them haven’t engaged once.
This is why source tracking is very important if you’re serious about list growth in 2025. You need to know exactly where every new subscriber came from. Was it a homepage pop-up? A gated lead magnet? A checkout checkbox? And beyond that, did they do anything once they got in? The first 7 days are critical. If they don’t open, click, or convert within that window, the odds they’ll ever do so drop by more than 70%, according to updated ESP data benchmarks this year.
We recommend running cohort analyses monthly where you are not just asking how many joined your list, but which source produced the most engaged subscribers. You might find that your quiz funnel adds fewer emails, but the people it brings in click at 4x the rate of your homepage form. Or that your webinar signups engage better than your discount-based lead magnets.
List growth with purpose is the name of the game now. So don’t just count heads… count momentum, engagement, the percentage of new signups who are still with you and still active 30 days later. Because in email, growth isn’t about getting big fast, it’s about growing right.
If you’ve made it through all eight metrics, then you’re thinking like the brands that win in 2025. Metrics like List Growth Rate, Bounce Rate, Click-to-Open Ratio, Unsubscribe rate aren’t just numbers – they’re the key to 10X your email marketing ROI and when you track them the right way, you stop guessing and start scaling.
Now, if something in this guide hit home, don’t let it sit in your notes. Open your ESP, pull your last campaign, and measure it.
And if you’re ready to 10X your ROI with a team that lives and breathes this stuff, we’re right here. At Abervin Digital, we don’t just write flows and build funnels. We build systems that convert quietly, reliably, and with data behind every send. Call us at +1 307-271-5184 or visit www.abervindigital.com. Whether you’re scaling your list, fixing deliverability, or launching from scratch, we’ll help you do it the right way.
