HTML vs Plain Text Email: What to Choose For Your Next Email Campaign?

Remember that children’s game where you take a daisy flower, pluck its petals, and say:” loves me, loves me not, loves me, loves me not…”?

Choosing HTML vs plain text email seems exactly like that. I can only imagine marketers, salespeople, and the rest of the bunch, plucking hairs from their heads saying: “HTML, HTML not, HTML, plain text not…”.

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In this article, I’ll offer:

A data overview of HTML vs plain text (to help with an informed choice)
A snapshot of HTML and plain text (key pros and cons to keep in mind)
Detailed explanation for each (HTML – Plain text)
Tips and tricks throughout to keep your hair in place

So, let’s kick off with some fun numbers to get your head spinning before the definitions, best-fors, and the rest.

HTML vs plain text email statistics

Finding reliable research into the performance of these email types/formats, was like playing darts with spaghetti. But, the grand revelations came from Litmus and HubSpot, though, I’ll also offer Mailtrap insights mixed in with email marketing stats from other resources.

The stats below are geared for the marketing and sales crowds. And the idea is to help you with the logic of plotting out email and drip campaigns.

The curious case of Litmus

Litmus ran the test on their webinar program targeting existing customers and non-customers. (Note: Customers vs non-customers is the critical vertical to keep in mind)
The main KPI were webinar sign-ups and they split the test 50/50. It meant, 50% of customers got an HTML email and 50% got the plain text version. The same logic was applied to the non-customers.

And the results?

~ 60% of the conversions from existing customers came from the plain text version of the email. To that, other metrics such as opens and clicks were also higher with that type of email.
~ 49% of the conversions from non-customers came from the plain text version. And, interestingly, it had a higher open rate, but a lower engagement (click) rate.
Also, Litmus ran a bunch of A/B tests to check if the email message copy affected the results, only to confirm the original findings.

What can you get from this?

To non-customers, the email format doesn’t really matter.
Both plain text and the HTML version have their place in email programs.
Your existing customers are likely to engage better with plain text emails. And we, at Mailtrap, can confirm that. The reason is the more personal feel of a plain text email. (It’s like someone’s talking directly to you instead of sending a catch-all template.)

Now, the story may seem simple – send plain text to existing customers and HTML-based emails to non-customers, or send plain text to all.

However, it’s not that easy.

Remember that Litmus, like Mailtrap, is a SaaS business, meaning that its audience might not behave the same as an ecommerce avatar where eye-catching HTML email templates could play a significant role in conversions.

Therefore, it’s best to check the industry-based data across different verticals to help you set realistic expectations about your campaigns.

More data to keep your hair in place

Here, I’m checking the averages with metrics such as deliverability, open rates, and clicks. Then, cross-referencing that by industries and sources (Mailtrap and competitors included). And I’m wrapping up with user preferences based on age groups.

Important Notes:

The data varies widely and that’s to be expected given the target audiences and this doesn’t, by any means, reflect email providers performance.
The data are for marketing and bulk emails, transactional messages typically have much higher numbers. I won’t go into transactional email details, but only briefly mention them where necessary.
The data includes HTML, plain text, MIME multipart_alternative (both plain text and HTML format in one email), and hybrid emails (simple mostly text-based HTML). The latter two fall under tips and tricks, I’ll talk more about them later, and note that MIME multipart_alternative emails are typically beyond the scope of marketers.

Beyond this point comes the head-spinning part I promised earlier.

Email deliverability

According to Statista, around 45.6% of all emails get identified as spam. And yes, this involves both HTML and plain text and everything in between. The number is huge, but also on the decline over a 12-year period.
Circumstantial evidence shows that overly complex HTML emails typically land in spam. And it’s true. But, it’s hard to put your finger on a number since more than a few other factors determine inbox placement (e.i. the email service provider you chose, domain health, etc.).
Based on HubSpot testing, plain text and HTML emails may have the same deliverability rates, but adding more HTML elements (like GIFs and images) significantly reduces open rates. Here are the numbers:

Opens drop 37% for a hybrid with a GIF vs plain text email (same copy)
Opens drop 25% for a hybrid with an image vs plain text email (same copy)
Opens drop 23% for heavy email template vs hybrid email (same copy)

To get a more complete idea of how to improve your deliverability, check our cheatsheet playlist below.

Open rates by industry

Retail and e-commerce businesses experience an average open rate of 35.90%.
Educational sectors report a higher open rate at 37.35%, possibly due to the direct and personal nature of communication deemed important by recipients.
Industries like finance and manufacturing have lower open rates of 26.48% and 32.03%, respectively, which might reflect less engagement with promotional content.

Click-through rates (CTR) by ESP

MailerLite reports a CTR of 3.01%.
Constant Contact and GetResponse have CTRs of around 2% and 2.89%, respectively.
At Mailtrap, CTRs range from ~1.8% to ~6.7%, with averages of ~3% where product updates and follow-up emails are among the top performers. (data for HTML emails)

Interesting Fact: Consulting services see remarkably high CTRs up to 25%, suggesting targeted content in these fields is very effective.

User preferences

Despite the rich features of HTML emails, many users prefer the simplicity and directness of plain text emails. For example, significant portions of consumers across all demographic groups, including 74% of Baby Boomers and 60% of Gen Z, find email to be the most personal communication channel, which potentially influences their preference for less complex email designs.
Based on the GetResponse Benchmark report, engagement rates can vary by the timing and frequency of emails. Optimal sending times are early morning (4-6 AM) and late afternoon (5-7 PM), which align with the start and end of the average workday, enhancing engagement. (applies to both formats)

Lastly, here’s a quick breakdown of the most representative data in a table.

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HTML vs plain-text email: pros and cons

Check the overview of both email formats based on pros and cons. I’ll also cover best practices here. These are like general guidelines you as a marketer should keep close at hand.

HTML emails:

Visuals and rich content: HTML emails allow for the inclusion of images, CSS styles, dynamic content, and other multimedia elements. These can make them more visually appealing and engaging (depending on the industry).
Compatibility issues: Not all email clients render HTML content consistently, which can affect how your email appears to the recipient. This inconsistency can sometimes lead to broken layouts or unviewable content. This goes double for mobile devices and clients like Gmail, Outlook, and Apple Mail.
Tracking and analytics: HTML emails enable detailed tracking of opens, clicks, and other interactions through embedded tracking pixels and coded links, which can provide valuable insights for optimizing campaigns.

Plain-text emails:

High deliverability: Plain-text emails are less likely to end up in the spam folder and generally have higher deliverability rates because they contain no hidden code that spammers could exploit.
Simplicity and compatibility: These emails consist solely of text and are stripped of any formatting, which ensures they work across all email clients and devices without issues.
Personal feel: Due to their simplicity, plain-text emails can feel more personal and direct, potentially leading to better engagement in scenarios where a straightforward message is preferred.

Best practices for email marketers and marketers in general:

I’d advise you to understand the audience’s preferences and the purpose of your email when choosing between HTML and plain text.

For example, a marketing campaign showcasing a new product might benefit from the rich visual capabilities of HTML, especially if it’s a physical or interactive product. Whereas, a product update/feature announcement might be more suited to a plain text format for clarity and universal compatibility.

To stress, the choice between HTML and plain text should be guided by the specific goals of your email campaign, the nature of your content, and your audience’s preferences.

However, I’d also suggest you try MIME multipart_alternartive and hybrid emails. Just to keep in mind, MIME multipart_alternartive is for email developers, not marketers. However, I’d like you to understand the overarching principle so you can request it from the dev.

So, what are they?

MIME multipart_alternartive – is a content type that appears in the server-side code of the email. It allows you to send both the HTML and plain text email to a recipient and, of course, they don’t get both at the same time. Instead, the plain text version of the email serves as the fallback if for some reason the recipient can’t get the HTML. Check our templates and code examples featuring this trick.
Hybrid emails – are emails with only basic HTML. They retain much of the functionality of typical HTML emails but are mostly text-based and usually only have CTA buttons as an interactive element.

HTML email

By definition, HTML (HyperText Markup Language) emails are sophisticated versions of standard emails that include formatting, styles, links, and multimedia content, making them resemble web pages more than traditional text messages.

Use cases:

Marketing campaigns: Extensively used in marketing to showcase products with vibrant images, animations, and even embedded videos to capture the recipient’s attention.
Customer engagement: By incorporating interactive elements like quizzes, polls, or embedded videos, HTML emails can transform a passive reading experience into an engaging interaction, increasing the likelihood of customer interaction and conversion. (Remember, you need to be sure these are deliverable and that your audience responds well to them)
Transactional communications: For updates like shipping notifications or order confirmations, HTML emails can include real-time tracking and interactive elements, providing a seamless experience for customers. But note that these are far from marketing emails, click here to check the key differences.

Benefits:

Personalization and segmentation: Advanced tools and AI can help tailor HTML emails to the preferences and behaviors of individual users, significantly increasing the relevance and effectiveness of the campaigns. And, of course, we got a tutorial on how to do it.

Brand consistency: HTML emails allow you to incorporate brand elements like logos, fonts, and colors, and a custom email signature, ensuring that every communication reinforces the brand identity.
Analytics and optimization: The ability to track interactions through embedded pixels and links in HTML emails provides valuable insights, allowing marketers to refine strategies and improve the effectiveness of their email campaigns.

As indicated, incorporating HTML emails into your digital marketing strategy can provide a more dynamic and visually appealing way to communicate with your audience.

But to stress, you need to be sure that’s what your audience desires.

Plain-text email

By now, it’s not hard to guess that a plain text email is a straightforward form of electronic communication that consists only of text without any formatting or multimedia elements such as images, hyperlinks, or HTML code.

This simplicity ensures the email is universally compatible with all email clients and devices, presenting the message exactly as typed, without any layout or style variations.

Use cases

Transactional updates: Plain text is ideal for transactional emails like order confirmations, where clarity and deliverability are more important than visual design.
Personalized communication: They are often used for personal, one-to-one communications where a straightforward and honest tone is prioritized over flashy content.
Accessibility: Given their compatibility with all email clients and simplicity, they are excellent for reaching audiences who may use older technology or prefer less complex emails. Also, since plain text emails are universally accessible, they accompany HTML emails as a fallback variant.

Benefits

Higher deliverability: Plain text emails are less likely to be filtered into junk or promotional folders.
Simplicity and focus: Without the distractions of graphics or layout designs, recipients can focus purely on the message, which can be especially effective for conveying urgent or personal content.
Greater open rates: As discussed earlier, numerous studies and tests have shown that plain text emails generally achieve higher open rates.
Enhanced click-through rates: As a reminder – despite their lack of visual and interactive elements, plain text emails often record higher click-through rates.

The bottom line is that you shouldn’t hesitate to incorporate plain text emails into your marketing strategy. Your subscribers may respond better to them, the email format won’t affect marketing automation, and they’re proven to be particularly effective for specific contexts where the message’s clarity and deliverability are more critical than its visual appeal.

I hope you enjoyed the snippet on HTML vs Plain Text Email comparison. If you did, I advise you to check out Mailtrap's blog. It provides lots of useful information for developers as well as marketers.