Email Marketing KPIs You Can or Can’t Do Without

MUST-HAVE email metrics

Must-have KPIs are crucial for analyzing the performance of any email campaign. We’ve singled out five top-priority metrics:

• Open rate
• Bounce rate
• Unsubscribe rate
• Spam complaint rate
• Click rate

Open rate

Description:

Open rate denotes how many recipients of the entire mail list opened the email campaign. For this to happen, the email has to be delivered successfully first. Then other factors come into play, such as the email subject line. The better engagement it provides, the higher the open rate will be. Therefore, always check the subject line of your email campaign with respective email testing tool. But, of course, you should not separate subject line as a key factor. The sender name is also viable. Emails sent from “Support team” and “Olga from Mailtrap” are likely to have different open rates. 

Which folder an email gets put in, the so-called inbox placement, is a huge deal as well. For example, Gmail may sort incoming emails into Primary, Promotions, Social, and others. Some users open emails mostly from the Primary and Social inboxes, while the Promotions can be neglected completely. 

Aspects such as brand recognition and email history also play an important role in the open rate. 

Formula:

Open rate = (total unique opens ÷ total recipients) × 100

Benchmark:

There are different opinions on the optimum open rate. It depends on the industry, purpose of the email, time of delivery, and so on. But most marketing experts concur that an open rate of <20% is a failure. 

How often you should track it:

Every week 

Bounce rate

Description:

Bounce rate denotes a ratio of bounced emails to all email addresses in the mail list. A bounced email is an email that failed to be delivered. There are two types of email delivery failure:

• soft bounce – which comes from a temporary failure, such as the recipient’s mailbox being full
• hard bounce – which comes from a permanent failure, such as an invalid email address

Read the blog post to discover more about the difference between hard and soft bounce. 

Formula:

Bounce rate = (all bounced emails ÷ total email recipients) × 100

Benchmark:

If less than 2% of your emails failed to end up in the recipients’ inboxes, that’s fine. Once you’ve stepped over this threshold, you need to invest effort in raising your delivery rate (the metric that is opposite to bounce rate). A double-digit value of email bounce rate is an alert signal – your sender reputation is at risk.

How often you should track it:

Every month

Unsubscribe rate

Description:

Unsubscribe rate is the ratio of the recipients who clicked Unsubscribe to the total number of emails delivered. As a rule, this metric shows how many subscribers lost interest in your product or service. At the same time, the reasons that lead to opting out may include:

• misleading subject lines
• emailing too frequently 
• ineffective offer
• and many more

Unsubscribe rate can point out how to fine-tune your email campaigns and filter out irrelevant subscribers. Segmenting subscribers will also help you reduce unsubscribe rates.

Formula:

Unsubscribe rate = (total unsubscribes ÷ total emails delivered) 

Benchmark:

A threshold value of unsubscribe rate is 0.5% per email campaign. This means that of 100 emails delivered, you may have up to 5 unsubscribes. 

How often you should track it:

Every week

Spam complaint rate

Description:

Spam rate denotes the ratio of the recipients who marked your email as spam to the total number of emails delivered. This is the most critical metric for your domain reputation and deliverability in general. 

Do not confuse this metric with the Spam score, which does not depend on the recipient’s attitude to your email. The spam score is sort of a ticket for your email campaign to pass through spam filters. If your email has a high spam score, it will go into the spam folder automatically. In the blog post Why Emails Going to Spam and How to Prevent It, you’ll find more on this. 

With the spam complaint rate, the destiny of your email is totally in the recipient’s hands. They can click “Mark as spam” for different reasons, such as:

• emailing too frequently 
• irrelevant content
• no opt-out option
• the recipient did not give consent for emailing

The last two points are especially important in terms of GDPR compliance. For more on this topic, read our blog post about GDPR for email marketing.

Formula:

Spam complaint rate = (total “marked as spam” ÷ total emails delivered) × 100

Benchmark:

The optimum spam complaint rate is below 0.1%. If it’s higher, your email marketing either targets false recipients or delivers poor value.

How often you should track it:

Every week

Click rate

Description:

Click rate, also known as click-through rate (CTR) defines how many recipients clicked on the links in your email. This metric depends on a few factors:

• credible and compelling content 
• email formatting
• anchor text on the link
• link location in the email body
• total number of links 

All this should convince a recipient to take an action and click the link. If the click rate is poor, this means that you failed to deliver your CTA or idea to subscribers.

Formula:

Click rate = (total unique clicks ÷ total emails delivered) × 100

Benchmark:

There is no maximum optimum click rate. The values differ by industries. For example, according to Constant Contact’s Knowledge Base, the average CTR in the transportation industry in September 2019 was 16.61%. Meanwhile, the average CTR in the travel and tourism industry was only 5.92%. 

How often you should track it:

Every week

To know more about email marketing metrics, check the article from the Mailtrap Blog.