How to Determine the Best Length for Your Email Subject Lines

As a marketer, you work hard to write great copy and create
compelling emails. But if you aren’t writing subject lines that
encourage subscribers to read your messages, your campaigns could
fall short.

More and more emails are opened on mobile devices, which
typically show fewer subject line characters. With this in mind,
you may wonder if your subject lines should be shorter to
accommodate on-the-go subscribers.

Is there a secret to the perfect subject line length?

Every subscriber list is different, so the perfect subject line
length depends on a variety of factors. But it’s possible to get
insight into ideal lengths for your industry.

In this post, we’ll share some actionable tips for finding the
correct email subject line length for your campaigns.

Factors to consider in your email subject line length

There’s really no such thing as a one-size-fits-all length. In
fact, the ideal length of your subject line depends on a variety of

1. What devices and clients your emails are read on

From 2011 to 2018, . In 2018, 61% of emails were opened on a
mobile device.

How to Determine the Best Length for Your Email Subject Lines


It’s also important to keep in mind that your subscribers use
a variety of different browsers and email clients. This further
contributes to the complexity of having a one-size-fits-all optimal
subject line length.

This chart shows the number of characters that display across
common devices and clients:

How to Determine the Best Length for Your Email Subject Lines


When considering the email subject line length that will work
best for your campaigns, consider using data to pinpoint subscriber
devices. Are most of your subscribers opening emails on mobile, or
are they sticking to their desktop?

Pro-tip for CM users: You can easily find this information in
your Campaign Monitor account, in the Campaign Reports section
under Email Client Usage. This will help you optimize your subject
line length.

Here are January 2019 statistics for the top 10 email devices
and client including market share:

How to Determine the Best Length for Your Email Subject Lines


Since most people are viewing emails on iPhones and Gmail,
optimize your subject line length to between 41 characters
(portrait view on an iPhone) to 70 characters for Gmail. (You
don’t want a broken experience because your
subject line is too long

2. Past email subject line performance

It’s also a good idea to look at which subject lines have
garnered high open rates in your past emails.

High open rates can occur because of deals you were offering,
the time of day, or the copy and sentiment in the subject line

Still, it’s worthwhile to take a look and see if any trends
emerge from your email open rates and the length of the subject

How many characters are optimal?

According to
data from Marketo
, 41 characters–or 7 words–seems to be a
sweet spot for email subject line length in 2019, which is about 10
characters less than the average subject line.

subject line length


Here are a few email subject lines paired with their character
length to give you an idea of what a 41 character-subject line
looks like:

Email Subject Line Character Count
Work Can Wait – These Sales are THAT Good 41
Make a Meatless Loaf Even Meat Lovers Will Love 47
Cyber Monday For Those Procrastinators 38
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to Be
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AnalysisSMB Expectations

As you craft your email subject lines, remember when and how
your subscribers are reading your emails.

If the majority of the opens are happening on iPhones, you’ll
want to use shorter email subject lines to get the most impact.
Additionally, keep your offer or CTA at the beginning of your
subject line where it’s most likely to be seen. You can also

use preheader text
to add more context to your subject lines in
the preview pane.

Email Subject Line


Testing your email subject lines

Your email subject line is one of the
single easiest elements
to test in your email campaign. Tests
can help you see how your email subject lines will look across
devices, as well as how they compare to shorter or longer

  • Send test emails to see how subject lines render on all
    devices. This will ensure your subject line reads well anywhere.
    Inbox Preview feature
    enables you to see previews of your email
    in over 25 different email clients before sending your campaign to
    ensure your email looks great in any inbox.
  • A/B test two different lengths. Certain email providers allow
    you to A/B test two different subject lines to see how they
    perform. Try testing a short and long version to see which performs

email subject line formula


Leverage email subject line best practices

Finding the ideal length for a subject line is an important step
in your email marketing, but subject lines are not just about
length. In order to see success, you’ll need to leverage general
best practices. Remember to:

  • Use different subject lines. If you use the
    same subject line over and over, it won’t excite your
    subscribers. New subject lines encourage subscribers to open emails
    to see the latest and greatest information you have to offer.
  • Use personalization. Use personalization
    right in the subject line by including subscriber names. You can
    use many other personalization options based on subscriber data.
    This data can be collected through your sign-up form or from other
    sources like Shopify
  • A/B test subject lines. You’ll never know
    what works best without trying different options, so test
    your subject lines
    to find the best one.

Optimal length for email subject lines in 2019

Email marketing continues to provide the
best return on investment
(ROI) versus other marketing channels
in 2019. This success still begins with a short, well-crafted
subject line compelling the recipient to open it.

5 email subject line best practices in 2019

While the length of email subject lines is still critical in
2019, how you use the characters allowed in a line of text is more
important than ever. This is especially true with the truncated
display–30-40 characters–on most mobile device screens.

1. Shorter subject lines: As discussed above,
research shows around 41 characters is the optimal length for a
subject line. Still, some marketing experts suggest going even

Backlinko founder Brian Dean says subject lines which on average

do not exceed 16 characters
have significantly higher open
rates. He attributes this to two factors.

First, emails with shorter subject lines are more likely to be

Second, brevity creates an air of mystery.

Per Dean’s thinking, the subject line “Are you available to
meet today at 11?” (38 characters) doesn’t have quite the same
impact as “Meeting at 11?” (14 characters).

2. Emojis: While
the debate about emojis
continues, the fact is they’re here
to stay. Their judicious use in subject lines can set your emails
apart in an inbox with seemingly endless stacked lines of text.

email subject line how to


There are
additional advantages provided by emojis
. A majority of
companies do not use them, and this may contribute to the
higher response rate
for emails which employ them. Plus, they
create powerful emotive storytelling, perfect for the shorter lines
of text on mobile devices.

3. Capitalization: While you may not be giving
much thought to how you’re capitalizing your email subject lines,
you should be! There are four basic styles:

  • How to write an email subject line (sentence case)
  • How to Write an Email Subject Line (title case)
  • how to write an email subject line (all lowercase)

The pie chart below shows how often marketing professionals use
each of these styles.

Email subject line tips


There are two important takeaways here. First, zero percent of
marketing professionals use all uppercase capitalization for
subject lines.

Second, despite lowercase capitalization only being used 6% of
the time, some marketing experts such as Val Geisler
attribute increased open rates
to it due to a more casual,
personal feel.

4. Personalize: Using the personal touch in
subject lines such as including the recipient’s name is a
standard technique to increase open rates. You can, however, based
on individual website page views or search terms, use other types
of personalization.

email subject line best practices


This is a powerful subject line because it’s short, asks a
question, and ties to previous recipient behavior. Consider doing
the same with your emails.

5. Avoid spam filters: Every
email which winds up in a spam folder is a missed opportunity for
an open, clickthrough, and sales conversion. That’s why,
according to extensive research was
done by Yesware
, you want to avoid using the following words in
subject lines.

email subject line length in 2018


There’s more to
avoiding spam filters
than word choice alone. (Using all
capital letters will take you there, too.) No matter what, delete
the above words and phrases from your subject lines.

Wrap up

At the end of the day, the best email subject line length
will vary from brand to brand. That means it’s best to test out
different lengths to see what works for you.

If you leverage your past data and test your subject lines,
you’ll be well on your way to knowing how long email subject
lines should be to encourage subscribers to open and take action
with your campaigns.

For more tips on writing email subject lines, check out our
guide to
15 powerful subject line words

The post
How to Determine the Best Length for Your Email Subject Lines

appeared first on Campaign Monitor.

Source: FS – Email Marketing Blogs!
How to Determine the Best Length for Your Email Subject Lines