If you’re investing time and effort into email marketing, you probably have one big question in mind: Is it actually working?
Most of us send emails hoping people will open them, read them, click links, and finally make a purchase or take action. But unless we track the right performance metrics, we’re just guessing.
Email marketing KPIs, or key performance indicators, are useful in this situation. They help you understand how your campaigns are performing, what’s working, what needs improvement, and how you can boost conversions.
Let’s explore the most important KPIs you should track—explained in simple and practical language.
Why KPIs Matter in Email Marketing
You may have sent the perfect promotional email or newsletter with great design and strong offers. But if you don’t track results, you will never know:
- Did people like the subject line?
- Did they click the CTA?
- Which email performed better?
- What’s stopping someone from converting?
KPIs give you real numbers and real insights, so you can make better decisions instead of relying on assumptions. They help you:
- Improve future campaigns
- Understand customer behaviour.
- Increase revenue
- Save time and marketing budget
- Boost conversions step by step
Top Email Marketing KPIs You Must Track
Open Rate
This indicates the number of people who opened your email.
A low open rate usually means:
- Your subject line wasn’t appealing enough
- Your audience wasn’t interested in the topic
- Emails landed in spam
- You chose the wrong send time
To improve open rate:
- Use catchy and benefit-driven subject lines
- Personalize the subject (“Hey Sam, we picked this just for you”)
- Send emails when your audience is most active
- Keep the “From Name” recognizable and trustworthy
When your open rates go up, your conversion opportunities automatically increase.
Click-Through Rate (CTR)
CTR indicates the number of people who clicked on the link within your email.
Even if someone opens your email, they need to take action—otherwise it won’t lead to conversions. CTR helps you measure:
- How convincing your copy was
- Whether your CTA (Call to Action) was strong enough
- How relevant the offer was
To increase CTR:
- Use simple and clear CTAs like “Download Free Guide” or “Shop Now”
- Place CTA buttons early and multiple times (top + middle + end)
- Use visuals to guide attention
- Make links mobile-friendly
If your CTR is strong, it’s a sign that your content is engaging and your offer is relevant.
Conversion Rate
In the end, this is what really matters.
Conversion rate measures how many email recipients completed the desired action—like buying, signing up, downloading, booking a call, etc.
For example:
- 500 people click your link
- 50 purchase your product
Conversion rate = 10%
Conversion rate tells you how effective your funnel is after the click, not just inside the email.
To boost conversions:
- Match email content with landing page messaging
- Reduce unnecessary steps in checkout or signup
- Offer limited-time deals or exclusive bonuses
- Include testimonials and social proof
A high conversion rate means your email strategy and your offer align well with customer needs.
Bounce Rate
Bounce rate represents how many emails failed to reach the inbox.
There are two types:
- Soft bounce – temporary delivery failure (full inbox, server issue)
- Hard bounce – permanent failure (fake/inactive email, wrong address)
High bounce rate damages your sender’s reputation and affects deliverability.
To reduce bounce rate:
- Clean email lists regularly
- Remove inactive or invalid contacts
- Use double opt-in for new subscribers
- Avoid buying email lists
Good bounce rate = better inbox placement = more opens and clicks.
Unsubscribe Rate
Nobody likes seeing unsubscribers, but it’s a valuable metric.
It shows how many people left your email list after receiving a campaign.
Unsubscribes happen when:
- Emails feel too frequent
- Content is irrelevant
- Audience expectations don’t match what you send
- You sound too salesy all the time
To reduce unsubscribe rate:
- Segment your audience based on interests and behaviour.
- Provide valuable content—not just promotions
- Give readers control (weekly vs monthly frequency)
- Set clear expectations when they join your list
Remember: some unsubscribes are normal. What matters is keeping the rate low.
Spam Complaint Rate
This KPI shows how many people marked your email as spam.
Even a small percentage can seriously hurt your sender score and inbox placement.
Common reasons for complaints:
- Sending without permission
- Unclear identity or misleading subject lines
- Too many emails in a short time
- No easy unsubscribe link
To avoid spam complaints:
- Always email with permission
- Use clear subject lines and brand identity
- Send helpful content consistently
- Keep an easy-to-find “Unsubscribe” button
When users trust your emails, conversions increase naturally.
List Growth Rate
Your email list should grow over time. This KPI tracks how fast your list is expanding after removing unsubscribers and inactive contacts.
Healthy list growth means:
- More reach
- More leads
- More conversions over time
Ways to grow your list fast:
- Offer lead magnets (eBooks, templates, coupons)
- Add subscribe forms on the website/blog.
- Promote signups on social media
- Add exit-intent pop-ups
The bigger and more engaged your list becomes, the more revenue your email campaigns can generate.
ROI (Return on Investment)
At the end of the day, ROI shows how much revenue your email marketing generates vs. how much you spend.
Email is known as one of the highest-ROI marketing channels—if executed properly.
Tracking ROI helps you understand if your campaigns are financially successful.
To improve ROI:
- Maintain a clean and active list
- Invest in personalization and automation
- Focus on delivering value consistently
- Retarget inactive subscribers with special offers
The higher the ROI, the stronger your email strategy.
How Tracking These KPIs Leads to Higher Conversions
When you combine all these KPIs, you get a complete picture:
- If the open rate is low, improve the subject line and timing
- If CTR is low, improve email content and CTAs
- If conversions are low, improve the landing page and offer
- If unsubscribe or complaints are high, rethink frequency and targeting
Every metric tells a story—and once you understand it, you can adjust your strategy and increase conversions step by step.
The smartest marketers don’t try random tricks.
They test, measure, optimise, and grow.
Final Thoughts
Email marketing is not just about creating good-looking emails. It’s about delivering the right message to the right person at the right time—and measuring performance along the way.
When you track and optimise the KPIs above, you will:
- Understand your audience better
- Improve your communication strategy
- Build stronger relationships
- Increase conversions and sales consistently
You don’t need to be perfect from day one. Just start measuring, learn from results, and keep improving.
The more data you collect, the more powerful your email marketing becomes.
FAQ’s
Why is tracking KPIs important in email marketing?
Tracking KPIs helps marketers understand what’s working and what’s not in their campaigns. It reveals audience behaviour, campaign effectiveness, and areas for improvement. Without KPIs, email marketing becomes guesswork and can lead to wasted budget and low conversions.
Which KPI matters most for increasing conversions?
All KPIs play a role, but conversion rate is the most important, as it shows how many subscribers completed the desired action. Open rate and CTR influence conversions too because people must open and click before they convert — so a balance of all three is essential.
How can I improve my email open rate?
You can increase open rate by using compelling subject lines, personalisation, sender recognition, proper timing, and avoiding spam triggers. Testing different subject lines (A/B testing) also helps identify what attracts your audience, leading to more opens and engagement.
What is a good click-through rate (CTR) in email marketing?
A good CTR varies between industries but generally ranges between 2% and 5%. More important than a specific number is continuous improvement through clear CTAs, relevant content, visuals, mobile optimisation, and segmentation to ensure each user receives content that truly interests them.
Why is my unsubscribe rate high, and how do I reduce it?
High unsubscribe rates usually indicate irrelevant content, too many emails, or over-salesy messaging. To reduce it, segment your audience, send valuable content, set clear expectations during signup, and offer frequency choices so users decide how often they want to hear from you.
What causes emails to land in spam, and how can I avoid it?
Emails go to spam due to misleading subject lines, poor sender reputation, spam keywords, or sending without permission. To avoid it, always take consent, deliver helpful content, use a recognisable “From Name”, and maintain a clean email list by removing inactive addresses.