{"id":90789,"date":"2026-08-10T18:19:23","date_gmt":"2026-08-10T18:19:23","guid":{"rendered":"https:\/\/mailrelay.com\/glossary\/email-marketing-metrics\/"},"modified":"2026-08-10T18:19:27","modified_gmt":"2026-08-10T18:19:27","slug":"email-marketing-metrics","status":"publish","type":"glossary","link":"https:\/\/mailrelay.com\/en\/glossary\/email-marketing-metrics\/","title":{"rendered":"Email marketing metrics"},"content":{"rendered":"\n

Email marketing metrics are the data points that allow you to measure the performance of an email campaign. <\/strong><\/p>\n\n

These figures let you track the effectiveness of your email campaigns.<\/p>\n\n

Thanks to these indicators, you can find out how many messages are delivered and how many people open them. <\/p>\n\n

They also show which links get the most clicks.<\/p>\n\n

Likewise, they help you spot unsubscribes, bounces, complaints, and areas for improvement.<\/p>\n\n

Metrics shouldn’t be reviewed in isolation. They are most useful when you compare them to previous results, meaning when you observe a trend.<\/strong><\/p>\n\n

<\/p>\n\n

What are email marketing metrics and what are they used for?<\/h2>\n\n

Email marketing metrics measure recipient behavior and the outcome of every send.<\/p>\n\n

They also let you evaluate the health of your list<\/a>, content quality, and strategy profitability.<\/p>\n\n

Some metrics describe deliverability, while others reflect engagement.<\/p>\n\n

For example, the delivery rate<\/a> indicates whether the emails reached the receiving server.<\/p>\n\n

Click-through rates<\/a> show if the content sparked interest. Meanwhile, ROI helps you determine if the campaign was profitable.<\/p>\n\n

With these metrics, you can compare subject lines, senders, designs, offers, and calls to action.<\/p>\n\n

They also let you study the behavior of different segments.<\/strong> This way, you can tailor your content to each group of subscribers.<\/p>\n\n

Additionally, they help you adjust your sending frequency. A spike in unsubscribes might indicate you’re sending too often.<\/p>\n\n

However,<\/strong> it could also mean that the content no longer meets the expectations set when they signed up.<\/p>\n\n

Analyzing this data allows you to answer specific questions.<\/p>\n\n

You can find out if the email arrived, if the subject line sparked interest, and if the content got clicks.<\/strong><\/p>\n\n

Not knowing this leaves you in the dark.<\/p>\n\n

You can also discover which link was the most effective and if the campaign generated sales, registrations, or downloads.<\/p>\n\n

This analysis becomes even more useful when the data appears in real time, as is the case with Mailrelay.<\/strong><\/p>\n\n

This way, you can spot issues during the send and act before they affect the entire campaign.<\/p>\n\n

Difference between a metric and a KPI<\/h2>\n\n

A metric is any measurable data point from a campaign.<\/p>\n\n

A KPI <\/a>is a metric linked to a specific goal.<\/p>\n\n

For example, the open rate might just be another data point.<\/p>\n\n

However, it becomes a KPI if your goal is to increase the visibility of your email campaigns.<\/p>\n\n

Not every email marketing metric has to be a KPI for you.<\/p>\n\n

Focus on a few KPIs and set a clear objective.<\/p>\n\n

Main email marketing metrics<\/h2>\n\n

The most important email marketing metrics depend on the campaign’s goal.<\/p>\n\n

However, there are several indicators you should check for every send.<\/p>\n\n

\u00b7 Delivery rate<\/h3>\n\n

Delivery rate<\/a> shows the percentage of emails accepted by the receiving servers.<\/p>\n\n

It lets you check if the message reached the contact’s email system.<\/p>\n\n

A low rate can indicate invalid addresses (b<\/a>o<\/a>unces<\/a>), blocks, or reputation issues.<\/p>\n\n

That’s why you need to check the quality of your database<\/strong> and the source of your contacts.<\/p>\n\n

Delivery doesn’t guarantee the message will appear in the main inbox.<\/p>\n\n

An accepted email can still end up in the spam<\/a> folder.<\/p>\n\n

\u00b7 Bounce rate<\/h3>\n\n

The bounce rate indicates the percentage of messages that couldn’t be delivered.<\/p>\n\n

Bounces can be hard or soft.<\/strong><\/p>\n\n

A hard bounce<\/strong> usually points to a non-existent or invalid address for some reason.<\/p>\n\n

On the other hand, a soft bounce<\/strong> is due to a temporary issue. For example, the inbox might be full.<\/p>\n\n

\u00b7 Open rate<\/h3>\n\n

The open rate estimates the percentage of recipients who opened the email.<\/p>\n\n

It’s best to analyze it as a trend.<\/strong><\/p>\n\n

\u00b7 Click-through rate or CTR<\/h3>\n\n

CTR measures the percentage of recipients who clicked on any link.<\/strong><\/p>\n\n

This is a direct sign of engagement with your content.<\/p>\n\n

A low CTR might indicate a lack of interest.<\/p>\n\n

It can also point to weak calls to action, a confusing design, or too many links competing for attention.<\/p>\n\n

To improve this metric, use clear and visible links.<\/p>\n\n

And, if possible, have a single goal for every email you send.<\/p>\n\n

\u00b7 Click-to-open rate or CTOR<\/h3>\n\n

CTOR compares unique clicks<\/strong> to unique opens<\/strong>.<\/p>\n\n

It helps you assess your content’s ability to drive action.<\/strong><\/p>\n\n

This metric separates the performance of the email body from the subject line’s initial effect in getting opens.<\/p>\n\n

That’s why it’s useful when testing designs, copy, and calls to action.<\/p>\n\n

A high CTOR<\/a> usually means the message meets the expectations set before opening.<\/p>\n\n

However, it should always be compared with the final conversion.<\/p>\n\n

\u00b7 Clicks per link<\/h3>\n\n

The total number of clicks doesn’t explain which elements performed best.<\/p>\n\n

To find out, you need to analyze each link individually.<\/p>\n\n

Clicks per URL show which destination attracted the most interest.<\/p>\n\n

Mailrelay lets you track all your links<\/strong>, no matter where they are\u2014buttons, images, menus, and in-text links.<\/p>\n\n

These email marketing metrics will help you see which parts of the email to prioritize, what your contacts notice most easily, and which calls to action you need to strengthen.<\/p>\n\n

With this information, you’ll also know which links never get clicked, or get very few and should be improved, or removed if they don’t add value.<\/p>\n\n

\u00b7 Heatmap or click map<\/h3>\n\n

A heatmap visually displays the most clicked areas of the email.<\/p>\n\n

This lets you identify the buttons, images, and text that draw the most interaction.<\/p>\n\n

For instance, a button might get few clicks because it’s placed too low.<\/p>\n\n

Or it might go unnoticed due to its size, copy, or position.<\/p>\n\n

The heatmap provides a highly visual context that numbers alone can’t offer.<\/p>\n\n

This helps you decide where to place calls to action in your next sends.<\/p>\n\n

\u00b7 Conversion rate<\/h3>\n\n

The conversion rate measures the percentage of recipients who completed the desired action.<\/p>\n\n

This action could be a purchase, registration, request, or download.<\/p>\n\n

To calculate it accurately, you must first define what counts as a conversion.<\/p>\n\n

Additionally, you need to connect the email clicks with the final outcome.<\/p>\n\n

This metric aligns your data analysis with your broader business goals.<\/p>\n\n

That’s why it’s usually more relevant than an isolated open.<\/p>\n\n

\u00b7 Unsubscribe rate<\/h3>\n\n

The unsubscribe rate reflects the percentage of people who opt out after a send.<\/p>\n\n

An occasional unsubscribe, or a few of them, usually isn’t a problem.<\/p>\n\n

It’s normal for people to unsubscribe over time.<\/strong><\/p>\n\n

In fact, a clean list can perform better than a list full of unengaged contacts.<\/p>\n\n

However, a steady increase might signal you’re sending too often or your content lacks relevance.<\/p>\n\n

Analyze this metric alongside spam complaints.<\/p>\n\n

If there’s a sharp spike in unsubscribes, it might be due to a specific issue.<\/p>\n\n

\u00b7 Spam complaint rate<\/h3>\n\n

This rate measures how many recipients mark the email as spam.<\/strong><\/p>\n\n

It should be kept as low as possible.<\/a><\/p>\n\n

An increase can damage your domain reputation and future deliverability.<\/p>\n\n

Above all, remember to offer a clear unsubscribe option.<\/strong><\/p>\n\n

\u00b7 List growth rate<\/h3>\n\n

The growth rate compares new signups with unsubscribes and lost contacts.<\/p>\n\n

It shows if your audience is growing sustainably.<\/p>\n\n

A large list isn’t always useful.<\/p>\n\n

Quality, engagement, and consent matter more than quantity.<\/strong><\/p>\n\n

That’s why you should combine this metric with clicks, conversions, and engagement levels.<\/p>\n\n

\u00b7 ROI compares the profit generated with the cost of your strategy.<\/h3>\n\n

It lets you assess the channel’s profitability.<\/strong><\/p>\n\n

You should include the cost of the platform, the team, design, and other resources.<\/p>\n\n

Then, link them to the revenue attributed to your email marketing.<\/p>\n\n

Among all email marketing metrics, ROI best connects your activity to financial results.<\/p>\n\n

\u00b7 The basic formulas are as follows:<\/h3>\n\n