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Saying your readers have the attention span of a goldfish is a bit of a stretch, but studies show that people receive on average 126 emails per day. With so many messages crowding inboxes, how much time do your readers actually have to read them? Not a lot.

If you want to make an impression, you’ll need to make it fast. With that said, what’s the ideal email length?

We’ll discuss the ideal email length and highlight strategies for different types of emails. Then, we’ll share our findings from A/B testing email length to optimize conversions and response rates.

Why is email length important?

Before we untangle what the ideal email length is, let’s go over why email length is important. Here are some reasons why:

• Many factors are competing for your reader’s attention.
• Readers often scan emails instead of actually reading them.
• Email clients “clip” emails that are too long or too large.

Let’s get into each of these reasons:

You’re competing for your reader’s attention

Readers receive on average 126 business emails a day. It’s unlikely they’ll devote a significant amount of time to each of these messages. In fact, studies show that readers spend about 51 seconds reading individual emails. Short emails with clear calls-to-action (CTA) are more likely to keep your subscribers’ attention than long emails.

Readers don’t actually read emails

According to a study by the Nielsen Norman group, email readers don’t actually read emails. Based on evidence obtained by eye-tracking software, the study found readers tended to simply scan email newsletters. In fact, readers often skip the introduction and only fully read about 19% of newsletter content. Use this knowledge to structure your email copywriting to deliver your content where you know it’ll be read.

Email clients “clip” emails that are too long or too large

Size matters. If your email is too long or too large, your subscriber’s email client may shorten your email. This means your readers will only see part of your email. To read your entire message, they’ll have to click on a link to open the rest of your email in a web browser. If you haven’t captured their interest in the first part of the email, they’re unlikely to follow a link to another page to finish reading your email.

More importantly, long emails could affect your deliverability. Some spam filters flag large emails as potentially harmful or spammy. Use email length best practices to help your emails land in inboxes.

Find out more about message clipping in Gmail.

What’s the ideal email length?

Now that we’ve covered the “why,” let’s discuss some email length best practices. Taking into consideration your subscribers’ email read rates, here are four areas to focus on regarding email length:

• Subject line
• Preheader text
• Email copy
• CTA

We’ll recommend an ideal length and give you some best practices. Let’s go over each of these:

What’s the ideal length for an email subject line?

An inbox is a crowded place, and you have to nail your subject line to stand out from the crowd. We recommend you start by accessing your email analytics to see the proportion of readers who open your emails on mobile devices. If your emails have a high percentage of mobile opens, you’ll want to keep this in mind when determining the length of your subject line.

So what does this mean?

Ideal length: About 28-50 characters, with 35 being a sweet spot for mobile devices.

Best practices:

• Use personalization techniques to engage your users and establish the point of your email.
• Preview your subject lines on different devices to ensure they display as intended.

What’s the ideal preheader text length?

Preheader text is the copy next to a subject line in the inbox. As you can imagine, preheader text plays an important role in helping you bag email opens. Think of this as a second chance (after your subject line) to grab your readers’ attention. With that said, what’s the ideal length for your preheader text?

Ideal length: 40-100 characters.

Best practices:

• Remember, some readers may open your emails on their mobile devices. Increase your open rates by ensuring your preheader text is mobile-optimized.
• Test your preheader text on different devices to ensure they display as intended.

What’s the ideal length for email copy?

Email copywriting is an essential part of creating good marketing emails. We’ve talked about strategies like the Problem, Agitate, Solve (PAS) method elsewhere, but let’s recap before we dive into the recommended word count.

When crafting your email copy, keep in mind your readers have a short attention span, tend to skip introductions, and scan the rest of your text. This means you need to make your email copy clean and to the point. A good email copy emphasizes important points, so your reader doesn’t miss key points of your email.

Ideal length: 50-125 words.

Best practices:

• A/B test your email copy in different segments of your mailing list to see what works best for your list as a whole and individual segments.
• Avoid basic grammar and style mistakes that impact your conversion rate and click-through rate.

What’s the ideal length for a CTA?

CTAs are arguably the most important part of your email content once your readers open your email. A well-crafted CTA drives clicks to your landing page and boosts your readers’ response rate.

You want your CTA to be specific and action-oriented. However, don’t make your CTA too long! You risk losing your reader’s attention.

Ideal length: 2-4 words.

Best practices:

• A/B test your CTA to see what works best for each segment of your mailing list. Should you target your reader’s fear of missing out (FOMO)? Should you appeal to their financially savvy side with a discount? Test out different CTAs to see what your audience responds to.
• Keep your CTA action-oriented and to the point.

What are the best strategies for each type of email?

Each email is different, and while our recommendations for specific email elements are a good place to start, let’s review some best practices for the types of emails your ecommerce business might send. Tailor your marketing strategy with these strategies:

• Newsletter: Use a teaser to get your reader’s attention and encourage interaction.
• Product announcement: Include a clear CTA to invite your readers to click through to your product landing page.
• Welcome emails: Provide key details to help your readers get started (or get purchasing!) right away. Keep it personal.
• Transactional emails: Encourage conversation by thanking your customers for their purchase and include personalized recommendations for other products they might like.
• Reactivation emails: Thank customers for returning and offer them incentives to stay, like discounts.

A/B testing for ideal email length 

We share a lot of content around email inspiration, how to code unique features into emails, and email design best practices. As an email SaaS brand, we’re constantly running A/B tests to improve our emails to send our audience messages they resonate with and enjoy. Our former Senior Email Marketing Manager, Paul Kirby, ran a few A/B tests to determine what Email on Acid’s ideal email length is.

Let’s take a look at Paul’s hypothesis, tests, and results. Finally, we’ll leave off with some takeaways.

The Hypothesis

Paul’s goal was to learn if emails with less than 100 words would earn higher engagement and click-throughs than ones with more than 100 words.

The Test

Paul tested multiple emails over two months to different list segments. During each test, one email had over 100 words, and the other had less than 100 words. There was approximately a 20-word difference between the two emails (give or take a few), which is about the length of a short paragraph.

The Results

In the vast majority of the sends, Paul found emails with less than 100 words achieve a higher click-through rate than emails with over 100 words. However, he notes the difference wasn’t always significant.

While the results aren’t 100% conclusive, they suggest our shorter emails can achieve more click-throughs.

Since there’s no real downside to sending shorter emails, we’ve been keeping our emails to 100 words or less when it makes sense. We only go over 100 words in instances where there’s a clear reason to, like in our monthly newsletter.

Takeaways

Your audience subscribes to your email list because your brand provides them value in some way. Learning how to communicate with your readers effectively is how a lot of small businesses grow. Take the time to run different A/B tests to determine how your readers prefer to experience and engage with your emails. Implementing your learnings will likely help you increase clicks and conversions.

And remember, what works for us at Sinch Email on Acid may not work for every organization. Don’t take our results on ideal email length as an industry best practice. Run regular A/B tests on your emails to learn more about your audience and send them content they can’t resist.

Wrapping up

Ensure your emails look flawless before you send them to your subscribers. Remember: It’s about more than just your email length. Content and design are also important.

To determine what your ideal email length is for your subscribers, you’ll need to run email tests to guarantee accurate email rendering previews. With Email on Acid, you can preview your email campaigns on dozens of live email clients and devices before you hit send. Sign up for our free trial and start testing today.

The article was updated on August 11, 2022. It was first published in September of 2019.