If B2B marketing had a “most misunderstood channel” award, email would take the trophy, probably delivered straight to your spam folder.
Despite predictions of its death since approximately five minutes after it was invented, email remains one of the most profitable, scalable, and controllable channels in any B2B marketer’s toolkit. It’s personal. It’s persistent. It gets results, when used properly.
But here’s the snag: ask ten marketers how they measure success, and you’ll get twelve different answers, three acronyms you’ve never heard of, and one confident soul shouting “open rate!” from the back. The result? Strategy sessions that go round in circles, campaigns optimised on guesswork, and dashboards cluttered with vanity metrics.
At Axon Garside, we prefer our data like our coffee: strong, clean, and capable of fuelling good decisions. This blog outlines the email marketing KPIs we actually monitor, the ones that help us move the needle for ourselves and for clients. Whether you're a CMO under pressure to prove ROI, or a marketing exec just trying to figure out why your click-through rate nosedived last Tuesday, you'll find something useful here.
We'll walk through the KPIs that matter most, why they matter, what they don’t tell you, and how to interpret them with context, not just copy and paste them into your next board report.
And since these metrics are part of a much broader inbound picture, we’ll be linking them back to your full strategy. If you're still stitching email campaigns onto your marketing like a patch on a sinking boat, now’s the time to upgrade your vessel.
10 Email Marketing KPIs We Monitor
When it comes to email, data isn’t the problem, it’s the interpretation. You’ve got a dashboard that looks like NASA mission control, but what does any of it mean?
Here’s our shortlist. Ten essential email marketing KPIs that we measure at Axon Garside, not just because they sound impressive, but because they help us make better decisions. For clarity, each one gets its own section below, with definitions, benchmarks (where they exist), pitfalls to avoid, and real-world insight.
No fluff. No filler. Just the metrics that move the dial.
1. Open Rate
Let’s start with the most abused metric in email marketing history.
Open rate is the percentage of recipients who (allegedly) opened your email. Historically, it’s been the go-to indicator for campaign performance, but in recent years, it’s started to resemble a lie detector on a polygraph test: useful in theory, wildly unreliable in practice.
Since the introduction of Apple’s Mail Privacy Protection (MPP), your open rate might reflect genuine interest, a bored intern, or a robot in Cupertino pretending to be Janet from Procurement. In other words: take it with a very large pinch of salt.
That said, open rate can still tell you something, especially when used comparatively. Subject line A vs Subject line B? Pre-header tweak vs no tweak? Time of day tests? That’s where open rate shines.
What’s a good open rate?
In B2B, open rates typically hover around 15–25%, depending on your industry, list hygiene, and whether you wrote “Free iPad” in the subject line (don’t). Just remember: higher isn't always better, it's what comes next that counts.
Common mistake:
- Treating open rate as the KPI to end all KPIs. It's not. It's a directional signal, a gateway metric, not a goal.
Watch out for:
- Inflated results from Apple Mail Privacy
- Trigger-happy filters blocking your content
- Sending to outdated or purchased lists (we see you)
When used in isolation, open rate can give you a false sense of success. But when paired with more reliable indicators like click-through and conversion, it still earns its place in the toolbox. Just don't expect it to carry the weight of your campaign on its own.
A well-rounded strategy considers how email sits alongside broader reporting priorities, and reviewing the B2B marketing KPIs you should be tracking across all channels can bring some much-needed clarity to the chaos.
2. Click-Through Rate (CTR)
There’s something oddly British about the obsession with open rates. We love a polite nod — a quick glance, a moment of interest, and then we move on without making eye contact. But in email marketing, polite nods don’t pay the bills. Click-through rate (CTR) is where the real action happens.
This is one of the email marketing performance metrics that truly tells you if your content is cutting through. It shows how many recipients clicked a link, in other words, how many went beyond a vague interest and took a definitive next step. It’s the difference between someone admiring a shop window and actually walking through the door.
And yet, we’ve seen marketers celebrate a 35% open rate while quietly ignoring the fact that nobody clicked a thing. That’s not engagement. That’s window-shopping with the blinds down.
If you’re serious about improving CTR, you’ll need more than a cleverly placed “Read More” button. You’ll need content that resonates, a clear and irresistible call to action, and ideally, a landing page that doesn’t look like it was built in 2009. If you’re unsure what sort of content actually drives behaviour, it might be time to revisit the types of content in B2B marketing strategy that get results, and no, “a long-winded company update” is not on that list.
As email marketing KPIs go, CTR is one of the most honest. There’s no bluffing your way to a good click, people either care enough to take action, or they don’t.
There’s no universal benchmark, but in B2B, 2–5% is a healthy target. If you’re consistently below that, ask yourself:
- Is your CTA clear, or are you hiding it like a legal disclaimer?
- Are you solving a real problem, or shouting into the void?
- Have you earned the right to ask for a click?
CTR is your first signal that your message landed, not just in the inbox, but in the mind. And unlike open rate, it’s refreshingly difficult to fake.
3. Conversion Rate
If CTR is the click, the conversion rate is what happens after. It's the difference between “That looks interesting” and “Here’s my data, take my money (or at least send me a downloadable PDF).”
As email marketing KPIs go, this one’s the clearest link to business value. It tells you how many people followed through on the action you wanted them to take, whether that’s booking a demo, downloading a guide, registering for a webinar, or completing the world’s shortest feedback form that still somehow took seven minutes.
The beauty of conversion rate is that it maps marketing efforts directly to outcomes. It doesn’t care how pretty your email looked. It doesn’t care if your open rate made you feel like a rockstar. It only cares about results.
It’s also one of the best ways to show leadership how to measure email marketing success. Because when your campaigns aren’t just engaging but converting, you’re not just filling the pipeline, you’re shortening it.
Of course, email doesn’t work in isolation. If your post-click experience is clunky, irrelevant, or has the emotional warmth of a tax return, you’ll lose people faster than you can say “unsubscribe.” That’s why conversion rate isn’t just about the email itself, it’s about what happens next. Your sales pages, your follow-up workflows, your alignment with sales, yes, actual alignment, not just vague nodding in meetings. If you're struggling there, start with this article on how to align sales and marketing.
In B2B, a good email conversion rate varies wildly depending on the offer, from 1–5% for top-of-funnel content to 10% or more for well-timed, highly targeted BOFU offers. What matters is that you’re measuring it consistently, tying it back to outcomes, and improving based on what works.
Because if your emails don’t convert, you’re not marketing, you’re just sending nicely formatted notifications into the abyss.
4. Bounce Rate
Nothing kills a campaign’s buzz quite like a bounce. You line up your email. Craft the subject line. Nail the pre-header. Hit send. And then half your effort smacks face-first into a wall of server errors, full inboxes, and email addresses that look suspiciously like someone sneezed on their keyboard.
Bounce rate is the cold splash of reality in your set of email marketing performance metrics. It tells you how many emails didn’t make it to their destination, and while some bounces are forgivable (temporary server blips, that one person who still uses Yahoo), others are the digital equivalent of sending a postcard to a demolished building.
There are two types:
- Soft bounce: The “Sorry, I’m not home right now” of email responses.
- Hard bounce: The “This address never existed, and frankly, how dare you” reply.
If your bounce rate creeps beyond 2%, it's a sign that your data hygiene routine is more ‘spray and pray’ than precision marketing. And if you're hitting 5% or more, you’re not running campaigns, you're hosting a memorial service for long-dead leads.
Before you panic, know this: it’s fixable. Clean your list. Stop buying data from “totally legitimate” sources that only accept payment in crypto. And brush up on how to improve B2B email deliverability before the inbox gods smite your sender domain for eternity.
Bounce rate might not get a standing ovation in boardrooms, but as email marketing KPIs go, it’s essential. After all, nothing else matters if your emails never show up. It’s the gatekeeper metric, the bouncer at the door of your entire campaign.
And if that bouncer thinks your list looks dodgy? You're not getting in.
5. Unsubscribe Rate
Every marketer has that moment. You open your campaign results, feel a flicker of hope, and then there it is. A handful of unsubscribes glaring at you like little digital break-up notes.
Relax. You’re not alone. And unless your email included Comic Sans, all caps, and a 25MB attachment, this isn’t a crisis.
Unsubscribe rate is one of those email marketing KPIs that gets unfairly demonised. But here’s the truth: people leaving your list isn’t always bad. Sometimes it’s just a polite “I’m not that into you”, and that’s fine. Better that than ghosting your open rate for six months straight.
Still, if your unsubscribe rate spikes (we’re talking above 0.5%), it’s time for a little self-reflection. Have you emailed too frequently? Gone too sales-heavy? Sent content with all the personality of a sandwich press manual?
Sometimes the culprit isn’t the email itself, it’s the disconnect between what your audience expected and what you delivered. This is especially common when email campaigns are rushed or written without real insight into the buyer’s mindset. If that sounds familiar, take five minutes to read up on blog writing for subject‑matter experts, because the best-performing content doesn’t just inform, it builds trust.
The best way to handle unsubscribes? Embrace them. Use them as a signal to tighten your targeting, improve your messaging, or just let go of the idea that everyone on your list still wants to be there.
Because if someone unsubscribes after five emails about your new whitepaper, chances are they were never going to download it anyway. And honestly? Good riddance.
6. Email Deliverability
Email deliverability is the unglamorous gatekeeper of email success. It’s not flashy, but it decides whether your carefully crafted message lands in someone’s inbox, or disappears into the digital abyss.
Low deliverability wrecks your email marketing KPIs before they’ve even had a chance. No open rate, no clicks, no conversions, just the silent sound of your campaign going nowhere.
The culprits? Poor list hygiene, erratic sending, spammy content, and yes, that cold campaign from 2021 you’re still pretending didn’t happen. Unlike many email marketing performance metrics, this one punishes quietly but thoroughly.
If you’re not checking deliverability regularly, don’t be surprised when results start dipping. A quick review of your B2B blog best practices is a solid starting point, good content habits often translate directly to email.
As a KPI email marketing metric, deliverability might not wow the boardroom, but ignore it and the rest won’t matter. After all, if no one receives your email, it doesn’t matter how clever the CTA was. You're just whispering into the void.
7. List Growth Rate
If your subscriber list hasn’t grown since the last Olympics, we need to talk.
List growth rate tracks how fast your email list is expanding (or shrinking, if things have taken a turn). It's one of those key email marketing metrics that gets ignored until the pipeline’s dry and someone from sales asks, “Why are we still emailing the same 200 people from last year?”
Spoiler: you should always be growing your list. Not chaotically, but strategically, with opt-ins that add actual value, not guilt-trip pop-ups that trigger the fight-or-flight response.
A healthy list does more than make you feel productive in front of your CRM dashboard. It also:
- Improves segmentation by giving you fresh data to target smarter.
- Boosts engagement as newer contacts are usually more active.
- Protects deliverability by reducing reliance on stale or inactive addresses.
- Supports long-term pipeline growth, not just campaign-by-campaign wins.
If you’re not actively attracting the right subscribers, you’re just squeezing more out of the same tired segment, and at some point, they will unsubscribe. Or worse, ignore you forever.
Want to attract new readers who actually want your content? Start with your lead magnets and landing pages, and make sure your content’s pulling its weight. Our free B2B blog template is a good example of how to structure content that earns attention and encourages opt-ins without resorting to emotional blackmail.
8. Revenue per Email/ROI
Now we’re talking real numbers.
Revenue per email and email marketing ROI are the KPIs that tend to make the boardroom lean in, usually right around budget review season, when someone’s trying to work out if your last five campaigns were a success or just… nicely formatted.
Let’s cut through the fluff. This is one of the few email marketing KPIs that connects directly to the bottom line. It tells you how much revenue each email generates, relative to what you spent creating and sending it. Or to put it bluntly: are your emails earning their keep?
There are two main ways to measure it:
- Revenue per email = total revenue generated ÷ total emails sent
- ROI = (total revenue - cost of campaign) ÷ cost of campaign × 100
It’s not just a number - it’s a narrative. A strong ROI tells a story of targeting done right, content that converts, and campaigns that justify their budget. A weak one… well, that’s when people start suggesting maybe social media “feels more modern.”
But here’s the rub: ROI doesn’t exist in a vacuum. To make it meaningful, you need clean attribution, a properly integrated CRM, and sales and marketing alignment that goes beyond “we had a meeting once.”
As email marketing metrics go, this is where accountability lives. Because if your campaign makes you feel warm inside but doesn’t generate revenue, you haven’t run a marketing campaign, you’ve hosted a very expensive group therapy session.
As email marketing KPIs go, this one’s a long game. But if you care about sustainable performance, audience growth isn’t optional, it’s the engine that keeps everything else moving.
9. Engagement Over Time
Let’s say your last email campaign went brilliantly. Open rate? Strong. CTR? Glorious. Conversions? Chef’s kiss. So… what happens next?
That’s where engagement over time steps in, the slow-burning, unglamorous cousin of your flashier email marketing KPIs. It’s not about single-campaign performance; it’s about trends. Patterns. The quiet evidence that your audience is either warming up, wearing out, or wandering off entirely.
This is one of those email marketing metrics that gets overlooked until something suddenly drops off a cliff. But tracking how engagement evolves week to week, month to month, tells you:
- When your audience is getting bored (before they show you the door).
- When content fatigue is setting in.
- Which send times, formats or themes perform best long term, not just once.
It’s also how to measure email marketing success beyond just “did we get clicks?” Because if engagement is steadily declining, even a high-performing outlier doesn’t mean you’re in good shape, it just means you had one decent Tuesday.
A few things to watch for:
- Gradual drops in open or click rates across multiple sends
- Sharp declines after changing frequency or tone
- Unsubscribe rates creeping up in parallel
Think of engagement over time as your email programme’s blood pressure. You won’t notice it until something’s wrong, but by then, it’s usually too late for a subject line tweak to fix it.
10. Email Read Rate
Open rates tell you who looked. Click-through tells you who acted. But read rate? That’s where you find out if anyone actually stuck around, or if they glanced, sighed, and went back to doomscrolling LinkedIn.
Email read rate tracks how long recipients engaged with your content. Did they read it, skim it, or bounce faster than a teenager asked to unload the dishwasher? For content-rich campaigns - especially those using zero-click formats — this is one of the email marketing KPIs that tells you whether your message landed or just flew straight past.
And before you ask, no - “time spent with the email open while I made a brew” doesn’t count. Most tools measure active engagement based on scrolling and interaction. It's not flawless, but it's better than assuming a 20-second open equals a deep emotional connection.
This is also one of the more underrated email marketing metrics when you're working with editorial or educational content. If your CTA is within the email, no landing page, no flashy download, read rate helps you gauge value delivery without the need for extra clicks.
Here’s how to improve it:
- Break up walls of text (no one’s here for a thesis).
- Front-load value: if they need to scroll to find it, they won’t.
- Write like a human, not an overexcited press release from 2009.
As KPI email marketing metrics go, this one doesn’t always get the attention it deserves. But if you’re putting effort into storytelling, formatting, and content structure, you deserve to know if anyone's sticking around to appreciate your efforts.
Otherwise, you’re just writing love letters your audience opens, squints at, and deletes while waiting for their UberEats.
Knowing What to Measure, and Why
If you've made it this far, congratulations, you’re officially more informed than most marketing dashboards.
We’ve covered ten email marketing KPIs that go beyond vanity metrics and actually tell you something useful. From open rates to revenue, bounce rate to read time, these numbers help you see what's working, what's not, and what’s quietly breaking everything behind the scenes.
But metrics are only useful when they drive decisions. So don’t just track for tracking’s sake, use your data to refine your strategy, guide your messaging, and build emails that do more than fill a slot in your content calendar.
Need help pulling it all together? Whether you’re chasing ROI, reviving your engagement, or just trying to stop your emails bouncing into oblivion, we’ve got a few ideas.
Ready to take your email marketing further? Download our B2B Email Marketing Guide for practical strategies, tips, and templates to turn your inbox output into pipeline impact.
Because good email shouldn’t just get opened. It should get results.