Email Deliverability: What is it and How to Measure it

are numerous ways to optimize your email marketing campaigns. None of them’s
more critical than building high deliverability.

after you’ve successfully reached your recipient’s inbox can you encourage them
to take action. Whether you want them to download your ebook, book an
appointment, or buy one of your products, your message won’t help you achieve
that if it’s stuck in the spam folder.

If you already know this much –
great! In that case, you don’t need more convincing. ☺

In this post, we’ll tackle two important topics: what is email deliverability and how to measure it.

And if you’d like to learn about improving your inbox placement and email campaign profitability, consider reading this article:

Email Marketing Best Practices

Bonus: Optimize your email campaigns with this Email deliverability Checklist and this comprehensive Email Deliverability A to Z Guide

What is email deliverability

Also known as inbox placement, the deliverability rate tells you how many messages reach your recipient’s inbox – or one of their folders/tabs (other than the dreaded spam folder).

You can calculate your email deliverability using the following formula:

[(# of emails delivered to the inbox/tabs/folders (excl. spam folder))/(# of sent emails – # of emails that generated a bounce)] * 100%

complicated? Let’s look at an example.

Let’s say you’ve sent out an email campaign
to 100 recipients. Out of those messages:

  • 60
    ended up in the recipient’s inbox
  • 30
    landed in the promotions tab
  • 5
    landed in the spam folder
  • 5
    generated a bounce

In this
case, you’d say your deliverability rate is 95%!

are the exact numbers we’ve used to arrive at this number:

[(60 +
30)/(100 – 5)] * 100% = 95%

we go any further, we’d like to make a small note first:

a whole argument of whether inbox placement is the right term to use when
referring to deliverability since we’re also counting other tabs and folders in
the equation.

think that the promotions tab (and other similar ones) was developed to help
email recipients manage and consume content they’ve subscribed to more

Although some marketers try to get their emails out of the promotions tab, given the latest developments from Google (leader in the market), we suggest that you think twice before you follow that path.

believe that happy recipients make happy customers. And Google has some pretty
cool plans for the promotions tab.

Problems with measuring email deliverability

theory looks simple, but measuring email deliverability isn’t an easy task.

you look into your email analytics dashboard, you’re usually missing one key
element from the equation – the number of emails that ended up in your recipient’s
spam folder.

Why is
that crucial piece of information missing? That’s because email servers your
messages are sent to don’t return this information. They may inform you about
the fact that the email address you’re trying to reach is inactive, or its
mailbox is full, but not what happened after the message was received.

the exact response you or your email service provider would receive regardless
if your message was placed in the inbox or the junk folder:

smtp;250 Ok

As you
can see, there’s no information as to how the message got filtered, i.e.,
whether it landed in the primary inbox, the promotions tab, or the spam folder.

This is
because how your emails get filtered within your recipient’s mailbox depends on
various factors – including how they interacted with your previous

other words, if your message ends up in the subscriber’s X spam folder, it
doesn’t mean it won’t show up in the primary tab for user Y or any other user,
for that matter.

So, if
it’s not possible to know when your emails end up in the spam folder, how on
earth do email deliverability tools work?

Three kinds of email deliverability tools

are three kinds of deliverability tools, and we’ll talk about them

1. Email spam checkers

Alright, the first set of tools we’re going to have a look at is called spam checkers.

they’re standalone tools; other times, they’re built into your email marketing
tool, as is the case with GetResponse.

checkers let you analyze the content of your emails and check them against spam
filters. They’re looking at various elements inside your email message like the
amount and types of links, images and their size, your coding, what’s inside
the headers, etc.

running a quick test with a spam checker, what you receive is the likelihood of
your emails going to spam. It’s usually presented on a scale from 1 to 5, where
5 means your chances to hit the junk folder are the highest.

are both pros and cons of using these types of tools.

Advantages of using spam checkers:

  • They’re
    quick – the test usually takes a few seconds
  • They’re
    easy to use – it’ll take you only one moment to learn how to use one
  • They’re
    rather powerful – based on hundreds of various tests, powered by
    industry-recognized programs like SpamAssassin

Disadvantages of using spam checkers:

  • They have limited scope – they only look at the content of your emails, excluding factors like recipient’s behavior or some of the ISPs filters

2. Seed list testing tools

way to check your email deliverability is to use seed email lists.

their simplest form, they’re just a bunch of email addresses that you send your
email campaign to, before launching it to your whole database.

email addresses are usually set up to include different ISPs (like Outlook or
Google), devices, and browsers.

sending your email campaign to a seed email list, you should know whether your
email is displayed correctly in all major email clients, whether it lands in
the inbox or returns a bounce.

that’s only theory.

As we
mentioned earlier, email deliverability is a bit more complicated than that.

Look Again Laurence Fishburne GIF by Leroy Patterson - Find & Share on GIPHY

already told you that when ISPs filter incoming emails, they also like to look
at how recipients respond to them.

If you
were to create a seed list and send your email campaigns to it and then open it
up for testing – what do you think would happen?

be giving signals to the ISP that these messages are important to you.

of that, these emails would more likely be placed in your inbox, which wouldn’t
necessarily be the case for other recipients of your emails.

your results could potentially be biased and give you a false overview of the
condition of your email deliverability.

you can create seed lists yourself, there are also professional tools that can
take care of the process for you.

just generate the list inside the tool, download and upload it as your regular
contacts to your email marketing platform, and then include them in your email

way of using seed lists sounds better in theory, but it also falls victim to the
same key drawback:

You get
quick access to a larger number of emails with various email client/device
setups – but these still aren’t real subscribers.

As a
result, even these tools won’t give you 100% information about your email

a quick recap.

Advantages of using seed email lists:

  • They
    have a different scope – unlike email spam checkers, seed lists can also help
    you identify email rendering issues
  • They
    can help identify important issues – they may sometimes show problems that
    won’t come up in spam checker tests

Disadvantages of using seed email lists:

  • They’re
    not based on real people – results from seed list tests aren’t 100% perfect,
    yet they may give you the false confidence that they are foolproof

3. Reputation management and monitoring tools

some tools let you monitor your mailing IP and domain reputation.

to these tools, you can see whether:

  • Your
    mailing IP or domain is listed on one of many blacklists that ISPs use when
    evaluating the incoming emails.
  • Your
    mailing IP or domain is set up correctly when it comes to aspects like SPF or

main advantage of having access to these tools is the ability to identify
technical factors that may be affecting your email deliverability.

explain this with an example:

say you haven’t changed anything about your email campaigns, but suddenly your
results dropped.

than checking your campaign with a spam checker or sending it over to a seed
list, the first thing you should do is use one of these reputation monitoring
tools and check whether your IP or domain has been added to one of the

these tools, much like the previous ones we’ve talked about, aren’t perfect.

Some of
the black- or graylists that appear on these websites aren’t of much importance,
and ISPs don’t even take them into account when evaluating incoming emails.

times, the lists are important, but the fact that you’re included in there
doesn’t mean your deliverability will be affected in any way.

instance, some lists include platforms that offer shared IP services, which is standard
among SMB email marketing services.

let’s put all this information together.

Advantages of using reputation
management and monitoring tools:

  • Additional
    angle – they give you insight into the more technical side of email marketing
  • They’re
    quick – you get information about potential deliverability issues within a
    moment of providing your IP address or mailing domain

Disadvantages of using reputation
management and monitoring tools:

  • Narrow scope – they don’t give you intel on your email content or how it renders in popular email clients
  • They may be confusing – they could falsely alarm you when everything’s fine
Pros and cons of email deliverability tools by GetResponse.

Summing up deliverability and spam check tools

As you
can see, each tool type has its advantages and disadvantages.

can’t say for sure that one is better than the other, as they’ve been developed
for different purposes.

you’d include all three of these types of tools into your email campaign

you may not always have enough time to do that, so just follow this flow:

  • If
    you’re developing an entirely new email campaign along with new message design
    – use a spam checker and a seed list.
  • If
    you’re revamping one of your older campaigns, altering the copy or overall
    design – use a seed list (even if it only includes a few of your colleagues)
  • If
    you’re experiencing deliverability problems, seeing high bounce and complaint
    rates – use all three types of email deliverability tools

It’s time to work on your email deliverability

With the theory out of the way, you’re fully equipped to start building a profitable email marketing program.

To learn more about the ways you can improve your email deliverability, make sure to read these posts:

  • Email deliverability best
  • Why emails go to spam and what you
    can do about it
  • Email marketing best practices for

And if you’re looking for an email service provider that’ll give you the technology and expertise required to run successful email campaigns, then go ahead and see how GetResponse Email Marketing solutions can help.

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