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How to measure the success of your email marketing campaigns
In our increasingly digital era, it’s easy to suffer from email overload. An average of 306.4 billion emails are sent every day – meaning we’re getting a lot in our inboxes, and not all of it welcome.
It’s no surprise, then, that 65% of emails are ignored as people prioritise their time towards those that they are expecting, or those that most interest them.

Despite these odds, email continues to be a very powerful tool for targeting customers but only if it’s done correctly. Using it in an effective way can deliver your message and proposition directly to your audience, encouraging them to take action and increase their engagement with your brand.
The more effective and aligned with your audiences’ interests the emails are, the better the results. Furthermore, by continuously optimising and monitoring the results, you are better placed to adapt and experiment with different techniques and messaging, which will help you to improve and evolve the process and increase those results.
This guide explains the email marketing metrics you should track to measure the success of your campaigns and why each matters.
Why is tracking your email metrics important?
For your email campaigns to be truly effective, you need to ensure that they align with the needs, interests, and preferences of your recipients. It can be challenging to get this right, especially in the early stages whilst you develop your understanding of your target customer and how they respond to your tactics.
By tracking the performance of every email that you send, you can learn about your audience’s behaviour. This will enable you to establish what works best, so you can embody it into your future campaigns for maximum results.
There is often a degree of experimentation required to find the perfect balance for your emails. Many brands will undertake A/B testing to compare different variables in their emails (such as headings, subject lines, images and wording). To do this, you need to collect and analyse the data to determine which brings the best response and then adapt the variables and content accordingly.
Monitoring your email metrics over time will also enable you to discover trends and patterns across several aspects that can optimise your campaigns fully. This includes the time/day you send emails, popular content offers, styles and formats. With this knowledge in your armour, you will be positioned to craft emails that have the effect you want them to and successfully engage recipients, rather than being ignored.
The metrics to track
Now that it’s clear why tracking email performance matters, it’s time to consider what metrics you need to analyse to gauge success.
It’s worth noting that the data you need to analyse will vary depending on the goals you are aiming to achieve. We’ve listed the most meaningful metrics that can be used as a baseline for tracking how effective an email is.
Open rate
One of the critical metrics used to analyse the performance of an email is of course the open rate. Your open rate tells you what percentage of recipients actually open the email.
Ideally, you want your open rate to be as close to 100% as possible. The average rate across industries is 21.33%, which isn’t very high at all – so to stand a chance of getting your email read by as many people as possible, you need to find ways to engage them.
If your recipients are not opening your emails, the most obvious takeaway is that the subject line and preview text aren’t doing their job, since this is all a recipient can see before they actually open the email. This text should be high impact and clearly indicate to the reader what they can expect when they open it. A/B testing different subjects and preview text will help you to find out what works best.
It’s worth noting that there are times when an email has slipped into the recipient’s junk mail, or simply that the recipient is just not looking to looking to engage or buy at that particular stage.

If you consistently send out quality emails, the contacts on your database will begin to recognise you as a valuable sender of content and consequently your open rate will continue to increase. Customers are much more likely to open an email from a brand they are already invested in or if the content suggested in the subject line interests them.
Click-through rate
Another key metric used to highlight email performance is the click-through rate (CTR). This shows how many people click the CTA (call to action) links in your email after they’ve opened and read the contents. These links might include opening a page on your website, such as a blog or product information, all of which can be tracked further using analytics.
Again, the higher your CTR, the better. A high CTR typically indicates that the recipient is taking the desired action of your email and progressing in their customer journey. The average tends to be between 2 and 5%.
It’s also worth reviewing which specific links your recipients are clicking (if there’s more than one in an email), so that you can see what interests them or stands out most, and then if they take further action.
If you are trying to improve your CTR, you should consider how you lead the reader to the click. For example, is the CTA clear? Does the other content in the email make the reader want to fulfil your CTA? Is the ‘clickable’ action given early on or buried in email copy?
You may want to utilise testing again here, such as experimenting with different wording or styles of your CTAs to see which secures the most clicks.
Bounce rate
If an email ‘bounces’, it means that it hasn’t successfully made its way into that person’s inbox, which might be due to an incorrect email address or server blocks (known as ‘hard’ bounces), spam filters, server faults or even lack of storage (known as ‘soft’ bounces). An email bounce rate tells you the number of people that actually do receive your email versus the number that you send it to.
In an ideal world, everyone you send an email should receive it (so that they can open, read and engage with it). You want the bounce rate to be as low as possible. The average is 0.7%.
If you are experiencing a high bounce rate – which could be anything above the average – it might be a sign that you need to purge or clean your database due to incorrect or inactive addresses or if certain recipients have blocked your emails.
By tidying up your database, you can ensure that the right people are on it, with the correct details, and focus your email efforts on them.
Conversion rate
A conversion rate tracks the number of people who complete the desired action from your emails. It may be linked to your CTR, though it may not necessarily be to click a link.
For example, if you send an email about a loyalty scheme your brand has launched, you might include a link to your website where they can find a form to join the scheme. While this is a click-through, the ultimate desired action is for them to fill in and submit the form. Only when this happens has the person ‘converted’.

As there may be many steps in a conversion, it can be hard to monitor and directly link to your email campaigns. Some tools will enable you to connect actions and emails so you can access the data you need to track conversion. However, it may also be a case of diving into your website analytics and mapping that onto your email activity to explore the relationship between activity.
A benefit of monitoring the conversion rate is so you can see the tangible benefits your email activity is having. It will show whether your emails are efficient at moving people along the buying funnel and encouraging them to make a purchase – which will ultimately drive your revenue and profit.
Unsubscribe rate
In line with GDPR practices, anyone who receives your email should be happy to do so and be given the option to opt out or unsubscribe at any time. If people are unsubscribing, you should track this for two reasons.
Firstly, an unsubscribe signals that someone does not want to receive your emails. While there are many reasons this could happen, it will typically suggest they aren’t getting value, which means you need to improve your emails to stop it from reoccurring. This could also highlight that you are targeting the wrong people, in which case you need to review your brand’s audience and rebuild your database accordingly.
Secondly, if you experience a high number of unsubscribes after a specific email, then it’s likely the issue is with the email itself. This gives you an opportunity to assess the campaign, adapt your approach and prevent your business from repeating old mistakes.
Monitoring your unsubscribe rate over time will also allow you to uncover patterns, such as changing consumer preferences or emails that result in the most unsubscribes. Armed with this information, you can then optimise your campaigns to keep people engaged and subscribed.
Subscriber count
In the same way that you should count those who are unsubscribing from your emails, you need to track who is subscribing. Ideally, you will look to grow your subscribers over time, as this builds your database, meaning more people have access to your emails, are interested in your brand and may be ready to do business.
Your subscriber count can increase because of growing brand awareness, which may stem from your other marketing efforts. Someone who chooses to subscribe to your email is also more likely to be engaged with your business, which can promote brand loyalty. However, it’s essential to continue to offer value to keep these people invested.
If your number of email subscribers isn’t growing – or worse, it’s falling – it could be a sign that you need to work harder to make people aware of your business and your email activity. This means making it easy for people to subscribe (such as a clear CTA to do so on your website or promoting your email newsletter on other channels) and ensuring your email campaigns are effective.
This is on top of the other activity you should be conducting to make people aware of your brand (therefore increasing the chances of them opting into emails), such as through SEO, social media, advertising and PR.
Return on investment
As with any activity you undertake, you want to make sure that you are getting a good return on your investment (ROI).
64% of small businesses use email marketing, suggesting there is value to be gained. However, you need to ensure it makes sense for your business and customers – and return on investment can indicate this by placing a monetary value on your email campaigns.
Return on investment (ROI) is unlikely to be included as a metric in a typical email marketing platform. As with conversion, it’s a little trickier to monitor directly.

To track ROI, you need to understand the financial benefits you are getting from your email activity. For example, if an email costs you £2 to create and send, but it results in three customers completing purchases totalling £10 each, your net return on investment is £28 or a rate of 1400%.
Of course, that is a very simplistic example, and it can sometimes be hard to determine precisely what led a customer to make a purchase. In these instances, tracking customer journeys and your website analytics (particularly traffic acquisition) can help you to map out the impact of your email campaigns, especially if you have your analytics set up to monitor email referrals.
It’s also worth noting that even if an email did not directly lead to a transaction, it might still have a return on investment through the nurturing of customer relationships and improving brand engagement. As such, ROI should not be considered as the be-all and end-all. Similarly, if the conversion happens offline (such as if your email is to encourage people to visit a store in person), you might need to rely on anecdotal evidence to prove the ROI.
That said, ROI can help you to demonstrate the value of your email efforts to other stakeholders in the business. If you see favourable returns, it can showcase your email marketing has worth in the business and even advocate for a larger budget to extend your campaigns. Due to its low cost to implement, email often has a high ROI – up to 4200%.
If a specific campaign has a high ROI, this can also be used as a marker for performance and highlight what practices you might want to mirror in future campaigns.
Domain and channel
When tracking email performance, it makes sense to also assess how people are accessing your emails. While this won’t necessarily tell you how successful an email is, it can help provide further context to your other data.
By analysing the domain and channel of your emails, you can see how people are choosing to view your emails and the open rates, CTRs and other engagement metrics split by separate channels/domains.
This will enable you to see the typical email providers your recipients are using and whether they’re using their desktop, tablet or phone. This matters because it will allow you to better understand your target audience’s behaviour and optimise your emails accordingly, such as making sure a campaign is designed for smartphones if that’s how people tend to view your emails.
If you experience bad CTRs, and your email isn’t built for the domain or channel your customers are commonly using, it could also explain why your performance isn’t better and indicate the need to improve.
By understanding this context, you can better align your campaigns to the proven behaviours of your audience and remove any barriers to engagement.
Conclusion
Email can bring incredible rewards to businesses. However, in a world where we’re bombarded with emails and messages, it’s crucial to perfect your approach and align with your target customers if you want to get any traction.
By monitoring your email performance, you can understand what works and what doesn’t. It will also enable you to experiment with different approaches until you find the optimum tactics for your campaigns that most engage your customers and move them along their purchasing journey.
Once you have spent time tracking the data, you will be able to master email campaigns, again and again, providing value for your recipients and driving tangible benefits for your business.