A Deep Dive into Deliverability Metrics

deep dive into deliverability metrics - mailmonitor

If there’s one simple truth about sending emails, it’s that your messages can’t be opened by anyone if they are unable to make it to the inbox in the first place. That’s why deliverability metrics are one of the most important things any email marketer should look into.

But first of all, what is email deliverability?

What Is Email Deliverability?

Email deliverability, sometimes referred to as inbox placement, is calculated by how many emails you send compared to the number of messages your recipients successfully received. Factors such as the internet service providers (ISPs), mailbox providers, spam issues, bounces, and throttling all affect a sender’s deliverability rate.

Every marketer who wants their email campaigns to succeed should ensure their email deliverability stays high. Here are a few reasons to consider it:

  • Emails that reach their target inboxes have a higher probability of being opened and potentially converting anyone who engages with them.
  • You get to prevent your messages from landing in the spam folder – an action that can negatively impact your sender reputation.
  • Since your emails will be arriving at the inboxes of your contacts, you’ll have an advantage over your competition when it comes to being more visible.
  • Messages that are received, opened, and engaged with successfully all increase positive email deliverability metrics.

What Are Deliverability Metrics?

There are many email deliverability metrics that marketers need to consider for their email marketing campaigns.

We’ve divided these metrics into positive and negative categories to make them easier for you to understand. Let’s discuss the positive ones first.

Positive Email Deliverability Metrics

The following are the positive metrics that indicate your email campaigns are off to a good start:

  • Open rate: Your email campaign’s open rate is the percentage of your contacts who have opened your emails.
  • Click-through rate: The click rate is a metric that dictates how many of your recipients have clicked on one or more links that you’ve included in your emails.
  • Click-to-open rate: This metric is calculated based on the total clicks divided by the number of opened messages.
  • Inbox placement rate: This is the number of emails that arrive in your contacts’ inboxes.
  • Read rate: Your read rate is the total number of messages that are considered “read” by your recipients out of all emails you’ve sent.
  • This is not spam rate: This is a metric that indicates the percentage of your emails that were labeled “This is not spam” by your contacts.

How to Improve Positive Email Deliverability Metrics

Here are some best practices to follow to improve your positive email deliverability metrics:

  • Open rate: One of the best ways you can increase a low open rate is by incorporating the name of your contact in your email subject lines. Segmenting your list into more personalized groups can help increase the relevancy of your messages, thus improving open rates.
  • Click-through rate: Optimizing your calls-to-action (CTAs) is an excellent technique to improve click-through rate. Consider using fonts that are easy to read and colors that are relevant to your brand in your CTAs.
  • Click-to-open rate: Ensuring that your emails are personalized and engaging are two methods of enhancing the click-to-open rate of your email campaign.
  • Inbox placement rate: Avoid blasting your contacts with too many messages, as this increases the risk of being flagged as spam or blacklisted by ISPs. Instead, set a schedule to send personalized emails that are hyper-targeted to your readers ahead of time.
  • Read rate: Consistently providing your subscribers with content that’s relevant to them can increase the read rate of your emails.
  • Spam rate: Besides avoiding bulk emails and using a clean email list, you should also employ email authentication to reduce the chances of your messages being marked as spam.

Negative Email Deliverability Metrics

Now that we’ve discussed the positive rates, let’s take a look at the negative email deliverability metrics that could hamper your campaigns:

  • Bounce rate: The bounce rate of your campaign is the percentage of emails that were returned due to not landing in their designated inboxes. It can be categorized into soft bounces and hard bounces.
  • Rejected or mail block rate: Similar to bounce rate, rejected or mail block rate happens when an email fails to send because of problems with the content or the sender’s reputation.
  • Complaint rate: Your email complaint rate is the percentage of users who marked your messages as spam.
  • Spam placement rate: The spam placement rate of your emails is a percentage of your messages that were redirected automatically to the spam folder upon receipt.
  • Deleted before reading rate: These are the number of messages that were outright deleted even before they have been opened.
  • Unsubscribe rate: This email deliverability metric indicates the percentage of contacts who have unsubscribed to your campaign.

How to Minimize Negative Email Deliverability Metrics

These negative email deliverability metrics are some of the most harmful rates that your email campaigns can experience. If maximizing the good metrics is part of best practices, then it stands to reason that minimizing your negative metrics is also part of this. That’s why it’s important to learn how you can minimize their percentages as much as possible.

Consider these tips to avoid increasing your negative email deliverability rates:

  • Bounce rate: The best ways to reduce your email bounce rate is by cleaning your email list regularly, testing your campaigns for effectiveness, and using double opt-ins.
  • Rejected or mail block rate: A few techniques to avoid being rejected or blocked is to not use certain trigger words, set up a whitelist, and stay compliant with the CAN-SPAM Act.
  • Complaint rate: You can lower your complaint rate by maintaining a permission-based email list. When your list is filled with users who have given you permission to email them, you ensure not only being flagged as spam but also higher engagement rates.
  • Spam placement rate: Using an appropriate subject line and writing clear content for your emails can reduce your spam placement rate. Your IP or domain address could also contribute to your spam rate, which is why you should ensure you sign up with a dedicated network — one that only belongs to you — instead of a shared network.
  • Deleted before reading rate: Since this metric indicates emails that were deleted even before they were opened, you want to make your messages to be personalized and relevant. The simplest way to do this is by applying these two techniques to your subject lines.
  • Unsubscribe rate: A common reason why people unsubscribe to mailing lists is that they feel that your content is no longer beneficial to them. By ensuring your emails provide value to your readers, you can minimize unsubscribes while keeping contacts engaged.

Your Sender Reputation Plays a Crucial Role in Your Email Deliverability

As hinted earlier, your sender reputation directly impacts your deliverability. Sender reputation is made up of three parts: IP reputation, domain reputation, and content reputation.

Your IP reputation is the standing of the current IP address you’re using. ISPs and anti-spam organizations track this type of reputation to decide whether they should allow or disallow your messages from passing through their filters.

The domain reputation is the overall reputation of the domain you’re using. Even if you change your IP address, your domain reputation will remain the same so long as you still use the same network.

Finally, your content reputation is the calculation of the relevancy and value that your email copy provides to readers. Although it can be difficult to assess, it basically measures how spam-like or valuable your content is to your recipients.

Is Sender Reputation and Sender Score the Same?

You might have heard about sender score, and it’s understandable if you mistake it for sender reputation. After all, these two are pretty much the same thing, except the other one provides a direct rating of your status.

If your sender reputation is your standing in the eyes of mailbox providers, ISPs, and anti-spam organizations, then your sender score is your actual rank in a numbered format. It reflects your sender reputation in numbers ranging from 0 to 100 – with 0 being the lowest and 100 being the highest.

Monitoring your sender score is important because it’s directly tied to your sender reputation.


Your email deliverability rate is one of the most important components you need to consider when sending out email campaigns. The main reason for this is because it dictates whether your messages will reach your contacts or not.

When your emails aren’t received, you won’t have the opportunity to sell your brand to your subscribers. That’s why you should keep an eye on your deliverability metrics, such as your open rate, click rate, spam rate, and bounce rate, to monitor your performance.

By following the tips provided above, you should be on your way to improving your email deliverability and ensuring that you have the best chances of landing in your target inboxes.

We offer tools and features that help you reduce negative rates and enhance the deliverability of your marketing campaigns