10 Essential email marketing metrics & KPIs for winning email campaigns

TL;DR

Email marketing continues to be one of the highest-ROI marketing channels, generating up to $45 for every $1 invested.
Email marketing metrics and KPIs help evaluate campaign performance by showing how effectively your marketing emails drive audience engagement and business outcomes.
Top 10 email marketing metrics to track include delivery rate, deliverability rate, open rate, click-through rate, conversion rate, bounce rate, unsubscribe rate, spam complaint rate, list growth rate, and total campaign revenue.
Maropost Marketing Cloud helps you improve email campaign performance with advanced reporting, revenue tracking, high deliverability, A/B testing, personalization, and send-time optimization tools.

Despite the ‘email is dead’ narrative we keep hearing every once in a while, email marketing remains one of the highest-ROI marketing channels. When done right, email marketing can deliver up to $45 in ROI for every $1 invested – and top brands are proving it.

But it only works if you consistently track the right metrics and KPIs, and use them to refine your messaging, timing, and targeting. Want to know if your subject lines inspire opens? Your open rates will show. Questioning whether your CTAs really resonate? Your click-through rate (CTR) will give you the exact answer. Analyzing your email marketing metrics and KPIs helps you move from guesswork to data-driven optimization.

In this blog, we’ll break down the top 10 email marketing metrics and KPIs every email marketer should be tracking. On top of that, we’ll provide actionable strategies to improve each one. Let’s get right into it.

What are email marketing KPIs and metrics?

Email marketing metrics and KPIs (Key Performance Indicators) are measures of the performance of different aspects of an email campaign. They help marketers evaluate the overall success of their email marketing campaigns by providing insights into the percentage of email recipients who opened an email, clicked through to your website from an email, and converted (e.g., made a purchase).

Beyond engagement and conversions, email marketing metrics also provide visibility into deliverability, list health, and the revenue impact of your marketing emails.

Top 10 email marketing metrics and KPIs you should be tracking and how to improve them

1. Delivery rate (server reach success)

Email delivery rate measures the percentage of emails that receiving mail servers accept for delivery. An email counts as delivered if it did not bounce. Your delivery rate is the first step in the journey your email message goes through after you hit ‘send’.

Delivery rate = [(Number of sends) – (Number of bounces) ÷ Number of sends] × 100

How to improve your email delivery rate:

Verify emails at the point of entry (use real-time validation tools on your sign-up forms to block typos and fake addresses from entering your list in the first place).
Monitor your bounce reports (categorize and analyze "soft" vs. "hard" bounces to identify whether delivery issues are due to temporary server glitches or permanent recipient errors).
Remove ‘hard bounces’ instantly (set your system to automatically remove permanently undeliverable addresses to protect your sender reputation).
Avoid using purchased lists (purchased email lists often contain fake or inactive addresses that can get your emails blocked).
Limit email file size (keep total email size under ~100KB to avoid rejections by strict mail servers).

2. Deliverability rate (inbox placement success)

Deliverability rate is the percentage of your emails that make it to your recipients’ inboxes – not spam folders. It is influenced by factors like sender reputation, email authentication, your list quality and hygiene, engagement signals, and sending volume and behavior. A good email deliverability rate typically ranges from 92% to 95%.

Deliverability rate shouldn’t be confused with delivery rate. Delivery rate simply shows you how many emails were successfully delivered, but it doesn’t tell you whether those emails actually reached the inbox. An email can technically be delivered and still land in the spam folder, where your subscribers won’t see it.

Deliverability rate = (Emails delivered to inbox ÷ Emails delivered) × 100

How to improve your email deliverability rate:

Ensure full authentication (fully authenticated domains (SPF+DKIM+DMARC) achieve 2.7x higher likelihood of inbox placement compared to unauthenticated ones, based on The Digital Bloom).
Use a double opt-in process (double opt-in reduces hard bounces, lowers spam complaints, and increases engagement).
Warm up new domains and IPs gradually (increase send volume slowly to build a positive sender reputation with mailbox providers).
Avoid "spammy" triggers (excessive use of caps, too many emojis in the subject line, or a suspicious "text-to-image" ratio can trigger filters).
Regularly remove disengaged contacts (keeping only engaged subscribers helps protect deliverability by ensuring your emails reach people who actually want to hear from you).

3. Email open rate (subject line effectiveness)

Email open rate is the percentage of your email recipients who opened your email out of the total number of successfully delivered emails. Some key factors that can influence your open rates are subject lines, timing, sender reputation, segmentation, and more.

A good open rate (typically between 20–40%) generally means that your subject lines are compelling enough to grab attention and get recipients to open your emails. It still doesn’t mean that your email campaign is effective, but it does help you see the entire picture.

Email open rate = (Number of emails opened ÷ Number of recipients) × 100

How to improve your email open rate:

Personalize your subject lines (personalized subject lines can increase open rates by up to 26%).
Add more context with a preheader (emails with a preheader see an average open rate of 44.67%).
Cut out spam trigger words (avoid using words that can trigger spam filters, such as “lowest price,” “discount,” “free gift,” and “act now”).
Use advanced segmentation (send highly targeted emails based on user behavior, as segmented email campaigns drive 30% more opens).
Optimize your send times (platforms like Maropost Marketing Cloud let you optimize send times based on each contact’s past engagement).

4. Click-through rate (engagement levels)

Click-through rate (CTR) is the percentage of your email recipients who clicked at least one of the links in your email. This is closely related to the click-to-open rate (CTOR) that measures how many people clicked a link among those who actually opened your email, which is why it’s typically higher than CTR. A good click-through rate falls between 2–5%.

CTR reveals how effective your email copy and calls to action (CTAs) are at driving user engagement and guiding them towards the desired action. Quick note: if your email content doesn’t meet the expectations set by your subject line, you can end up with decent open rates but very little actual engagement.

Click-through rate = (Number of people who clicked on a link in the email ÷ Number of emails delivered) × 100

How to improve your click-through rate:

Align your subject line with your content (if users open the email and don’t see what’s promised, they’re unlikely to click).
Focus on one clear goal per email (too many CTAs can be overwhelming, while a single, well-defined action makes it easier for users to click).
Write your CTAs in first person (using first-person language in your email CTAs can increase click-through rates by 20%).
Ensure your email design is mobile-friendly (in 2025, more than 55% of email opens worldwide came from mobile devices, based on Genesys).
Personalize using real behavioral data (emails that reflect a user’s behavior, preferences, and past purchases feel more relevant and are more likely to generate clicks).

5. Email conversion rate (goal achievement success)

Email conversion rate is the percentage of your email recipients who performed a specific action, such as making a purchase or downloading a resource. This is one of the most critical metrics to track to evaluate the effectiveness of your email marketing campaigns.

What’s important to mention here is that the average email conversion rates differ depending on the type of emails you send. For example, some email types, like abandoned cart messages, typically convert at much higher rates (around 4–5%) compared to standard promotional newsletters, which average closer to 1%.

Conversion rate = (Number of people who took the action ÷ Number of delivered emails) × 100

How to improve your email conversion rate:

Optimize your landing pages, not just emails (ensure landing pages match the email’s message and load quickly).
Personalize as much as you can (e.g., include relevant product recommendations based on a user’s past purchases and preferences).
Create a sense of urgency (use dynamic elements like live countdown timers or "low stock" indicators to create a sense of urgency and scarcity).
Use social proof to build trust instantly (if your conversion goal is a purchase, include product star ratings and testimonial snippets in your emails to build trust).
Optimize send times for conversions (with Maropost Marketing Cloud, you can set your emails to be sent at times when users are most likely to convert based on past behavior).

6. Bounce rate (list hygiene quality)

Email bounce rate is the percentage of your emails that failed to be delivered to recipients’ inboxes. These failures fall into two categories: ‘soft bounces’ from temporary issues and ‘hard bounces’ caused by invalid or inactive email addresses. Your bounce rate should stay under 2%.

Soft bounces happen due to issues like full inboxes or server downtime, and most email platforms will attempt to resend the message a few times. But when you get hard bounces, you need to get rid of them instantly, because they signal invalid addresses, and continuing to send to them can damage your deliverability.

Bounce rate = (Number of bounced emails ÷ Number of emails sent) × 100

How to reduce your email bounce rate:

Remove hard bounces immediately (invalid or non-existent email addresses should be suppressed as soon as they bounce).
Remove role-based emails (avoid sending to addresses like info@ or admin@, these are often monitored by multiple people and have higher bounce/spam report rates).
Use double opt-in (confirming email addresses at signup helps prevent typos and fake addresses from entering your list).
Clean your list regularly (periodically remove inactive, outdated, or unengaged contacts to keep your list healthy).
Avoid sending to purchased or scraped lists (these lists often contain invalid email addresses and lead to high bounce rates).

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7. Unsubscribe rate (relevance or frequency issues)

Unsubscribe rate is the percentage of your subscribers who opted out of receiving future emails from you. While unsubscribes can be demoralizing, some churn is natural and can help you identify issues with email relevance or send frequency. Your unsubscribe rate should ideally be under 0.5%.

In 2025, businesses saw higher unsubscribe rates because major mailbox providers like Gmail and Yahoo have made it easier for users to view and manage subscriptions, while also increasing visibility of unsubscribe options.

Unsubscribe rate = (Number of people who unsubscribed ÷ Number of emails delivered) × 100

How to reduce your unsubscribe rate:

Set expectations upfront (be transparent at signup about how often and what type of content you’ll send to avoid disappointment later).
Implement a ‘Preference center’ (a well-designed preference center can help you reduce unsubscribe rates by up to 30%, according to data from Digioh).
Deliver value-first content (irrelevant, generic, or overly sales-heavy emails are one of the most common reasons subscribers leave).
Segment audience by behavior (increase the relevance of your messages by using behavioral triggers).
Perfect your timing and cadence (about 44% of recipients unsubscribe because they get emails too often, based on stats published by Snov.io).

8. Spam complaint rate (reputation health indicator)

Spam complaint rate is the percentage of your recipients who marked your emails as ‘spam’. The more spam complaints you get, the more likely it is that your future emails will go straight to your subscribers’ spam folders instead of inboxes, affecting your deliverability. Your spam complaint rate should stay below 0.1%.

Unlike unsubscribes, spam complaints can directly harm your sender reputation, so even a small increase should be taken seriously. Keep a close eye on your complaint rates and act quickly if they start to rise.

Spam complaint rate = (Number of people who reported an email as spam ÷ Number of emails sent) × 100

How to reduce your spam complaint rate:

Implement double opt-in (using double opt-in helps you avoid accidental sign-ups that lead to complaints).
Make unsubscribing easy (if a user can't find the unsubscribe link, they’re more likely to hit the ‘Report Spam’ button instead).
Be instantly recognizable (use a consistent "From" name and clear branding so your subscribers never have to wonder who you are or why you’re in their inbox).
Control your sending frequency (sending emails too frequently can overwhelm your subscribers and increase your spam complaint rate).
Practice aggressive list hygiene (remove inactive subscribers who haven’t opened an email in over 90 days, as they are the most likely to flag you as ‘spam’).

9. List growth rate (audience expansion speed)

List growth rate measures how quickly your subscriber list is growing over a specific period of time. It accounts for new signups as well as people who unsubscribe or drop off, helping you see whether your email audience is increasing or shrinking. A good list growth rate typically ranges around 1-3% per month for mature lists.

List growth rate = [(Number of new subscribers) – (Unsubscribers in a given time period) ÷ Number of people on your list] × 100

How to increase your list growth rate:

Offer high-value lead magnets (give people a compelling reason to trade their email address, like a discount, an exclusive guide, or a template).
Minimize form friction (reduce the number of required fields to just an email address (or name and email) to lower the barrier to entry).
Promote subscriptions across channels (add signup opportunities to your website, social media, and paid campaigns).
Capture subscribers at key moments (use pop-ups, exit-intent forms, or post-purchase opt-ins when user interest is highest).
Use social proof (display your total subscriber count to build instant credibility and trigger a "fear of missing out" for new visitors).

10. Total campaign revenue (overall financial impact)

Total campaign revenue is the bottom-line metric that measures the total amount of money generated by a specific email campaign. It shows the overall financial impact of your email marketing strategy and helps you understand how your campaigns perform in terms of overall business impact.

Total Campaign Revenue = (Number of conversions) × (Average Order Value)

How to increase total campaign revenue:

Add dynamic product recommendations (include personalized product recommendations within emails based on a subscriber’s past browsing and purchase history to increase conversions and AOV).
Send emails at the right times (leverage send-time or conversion-time optimization to reach subscribers when they’re most likely to purchase).
Segment by Customer Lifetime Value (send exclusive, high-ticket offers specifically to your "VIP" segment, who are more likely to spend more per transaction).
Create artificial urgency (use countdown timers or "limited-time only" language to nudge subscribers into making a purchase decision quickly).
A/B test your offers (experiment with different incentives to see which one actually drives more total dollars rather than just more clicks).

How Maropost helps you run efficient email marketing campaigns

While continuously tracking your core email marketing metrics and KPIs is critical – and something every email service provider supports through built-in reporting tools – there’s more to consider if you want to ensure the success of your email campaigns. Here’s what Maropost Marketing Cloud offers to email marketers beyond the standard reporting and analytics tools:

Custom reporting options: With custom reporting options, you can build tailored performance reports based on the metrics that matter most to your business. Instead of relying solely on pre-built dashboards, you can define exactly what data you want to see, automate delivery, and share insights with your team.
Product and revenue tracking: Maropost Marketing Cloud enables you to connect product and revenue data to your email marketing campaigns, helping you build more targeted segments, personalize campaigns based on real buying signals, and clearly measure how your email marketing efforts impact revenue and ROI.
98% email deliverability rate: Poor deliverability can kill even the best campaigns before your messages ever reach your subscribers. Maropost ensures a 98% deliverability rate by using adaptive delivery that automatically adjusts send speeds based on real-time signals from each mailbox provider.
Dedicated deliverability support: If your emails still keep landing in spam folders, our dedicated deliverability support team will create a tailored remediation plan to restore your inbox placement. It has helped our clients recover hundreds of thousands of dollars in revenue that would have otherwise been lost.
A/B testing campaigns: With A/B testing campaigns, you can easily choose what you want to test (subject lines, preheaders, content, sender’s name, or send times) to understand what resonates best with your audience and use those insights to make changes that add up to better engagement and conversions.
Email personalization tools: Personalization can significantly impact your open rates, CRT, and conversions. Marketing Cloud lets you add dynamic content blocks and personalized product recommendations to your emails to make every message feel more relevant and tailored to each contact’s behavior and preferences.
Send-time and conversion-time optimization: With send-time optimization, your email campaigns are delivered at the day and time each contact is most likely to open them, based on past engagement. And conversion-time optimization goes even further by sending emails when contacts are most likely to make a purchase, based on their online purchase behavior.

Book a demo call now to see Maropost Marketing Cloud in action and learn how it can help you turn your email marketing campaigns into success – while giving you all the tools you need to measure performance and optimize each campaign for higher conversions.

Frequently asked questions

Why should I track email marketing metrics?

Tracking your key email marketing metrics and KPIs helps you understand how your email campaigns are performing and whether they are generating real business results. By monitoring open rates, click-through rates, and conversions, you can easily see what resonates with your audience and what needs improvement. Plus, it lets you spot technical issues (like poor deliverability or domain reputation) and fix them before they impact revenue. Ultimately, consistent tracking ensures you aren’t wasting budget on strategies that fail to convert.

What are the top 5 most common email metrics and KPIs?

The open rate is the most widely cited metric to track, showing you how effective your subject lines are at capturing attention. The click-through rate is the primary indicator of engagement, measuring the percentage of people who clicked a link within your email. Conversion rate shows whether your emails are driving meaningful actions (like purchases or sign-ups). And lastly, metrics like bounce rate and unsubscribe rate help you monitor list hygiene and whether your content remains relevant to your audience.

What are good email marketing benchmarks?

Good email marketing benchmarks can vary by industry, email type, and audience. But in general, for most businesses, a 20–40% open rate, 2–5% click-through rate, and 2–3% conversion rate are considered solid benchmarks. Technical benchmarks remain strict: your bounce rates should typically stay under 2%, spam complaint rates below 0.1%, and unsubscribe rates under 0.5%.

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