Plain Text Versus HTML Emails: My Testing Results

You've probably opened the same newsletter in two versions and wondered why one feels like a personal note while the other feels like a campaign. I've made that choice thousands of times. Plain text is faster, calmer, and often better for replies. HTML gives me hierarchy, branding, sponsor placements, and clearer paths to click. The right answer depends less on taste than on what the email has to accomplish.

Table of Contents

• The Format Choice That Actually Matters
  • Why the choice affects growth
• Reading the Engagement Benchmarks
  • Where HTML earns its place
• Deliverability and Inbox Placement Realities
  • What I check before blaming the format
• Reader Perception, Trust, and Accessibility
  • Plain text isn't the whole accessibility solution
• Production Workflows and Platform Experiences
  • How I use each platform
  • The hidden cost of HTML
• A Practical Multipart Strategy
  • My setup sequence
  • What I measure
• When to Choose Plain Text and When to Use HTML
  • My decision test

The Format Choice That Actually Matters

I changed my default format after one newsletter test. I had been using polished HTML templates because that's what most email tutorials recommend. Then I sent a clean plain-text version to one audience segment and a branded HTML version to another. The plain-text message produced stronger engagement across the metrics I cared about, including replies. I stopped treating design as the automatic starting point.

That result made sense once I looked at the reader's experience. Plain text resembles a note from a person. It has no layout to decode, no image blocking to work around, and no button that competes with the sentence around it. HTML can still be excellent, but every visual choice adds another place where the message can become noisy or fail to render properly.

Why the choice affects growth

Format changes more than appearance. It affects how quickly I can write, how naturally readers reply, how many links I can present without clutter, and how much testing I need before sending. It also changes what I can measure. HTML supports richer tracking, while plain text usually gives me less visibility into opens and presentation.

Mailbox providers don't make the decision simple. A properly coded HTML message can deliver well, while a badly written plain-text message can still generate complaints or weak engagement. The format is one signal among many, not a magic inbox pass.

My working rule: I choose the format that makes the reader's next action obvious. If that action is replying, I start with plain text. If it's comparing products, scanning sections, or evaluating a sponsor, I usually need HTML.

I also learned not to make the decision permanent. A founder update can be plain text one week and structured HTML the next if the content demands it. The mistake is building a heavy template before understanding whether the audience wants a conversation or a publication-style reading experience.

Reading the Engagement Benchmarks

The large benchmarks make plain text look like the obvious winner, but I read them as directional evidence rather than a universal command. One analysis of more than 4 billion emails reported 24.3% opens and 5.7% clicks for plain text, compared with 20.6% opens and 4.6% clicks for simple HTML. The same report found that plain text had a 21% higher open rate, 17% higher click rate, and 8% higher click-to-open rate than HTML, while heavy HTML recorded 17.4% opens and 3.3% clicks. The figures are reported in this plain-text versus HTML benchmark analysis.

Those numbers match the pattern I see when a designed email becomes too busy. The reader has to identify the main story, locate the useful link, understand the button labels, and decide whether the message feels like something worth opening again. Plain text removes most of that friction. It lets the writing carry the email.

Another industry summary reported that plain text generated 60% of conversions among existing customers and 49% among newer recipients in a 2022 analysis. It also cited more than 1,000 campaigns, where plain text outperformed HTML by 21% on open rate and 17% on click-through rate. A separate analysis of 500 million emails reported 42% more clicks and 25% better open rates for plain text. Those figures appear in Stripo's benchmark summary.

Where HTML earns its place

I don't discard HTML because its average engagement is lower. I use it when structure carries meaning. A product roundup, data-heavy briefing, event invitation, or sponsor placement becomes harder to scan when everything is reduced to paragraphs and raw links.

HTML also gives me more control over hierarchy. I can separate the lead story from secondary links, label a sponsor clearly, and use live text instead of putting critical information inside an image. That matters when a reader is skimming on a phone.

I keep subject-line decisions separate from format decisions. A plain-text email still needs a clear promise, and my newsletter subject-line testing guide is where I document that process.

The practical conclusion is narrow. Plain text often wins when the email is primarily a message. HTML earns its cost when the format helps readers understand, compare, or act on information. I don't judge either version from one percentage. I compare the actual task the email asks the reader to complete.

Deliverability and Inbox Placement Realities

Plain text doesn't automatically reach the primary inbox, and HTML doesn't automatically go to spam. I've seen clean HTML from an established sender behave better than a careless plain-text campaign from a new domain. Sender reputation, recipient behavior, authentication, list quality, and message structure all affect the outcome.

The clearest benchmark distinction is between transport delivery and inbox experience. One analysis of more than half a billion marketing emails found HTML and plain-text versions delivered at the same rate, with the meaningful differences appearing in inbox placement and engagement rather than raw delivery. Inboxwarm's analysis makes that distinction explicit.

What I check before blaming the format

When an HTML send underperforms, I don't immediately convert the whole newsletter to plain text. I inspect the message itself.

• Code weight: I remove decorative blocks that don't help the reader.
• Link behavior: I check every destination and reduce unnecessary link repetition.
• Image dependence: I make sure the email still communicates when images are blocked.
• Text alternative: I confirm that the plain-text part contains the actual message, not an empty fallback.
• Audience signals: I compare complaints, replies, clicks, and placement by mailbox provider.

HTML becomes risky when it's heavy, image-led, or assembled by an editor that produces bloated markup. Simple HTML with live text and a genuine plain-text alternative behaves very differently from a template packed with visual modules.

The cold-email evidence is more uneven. Independent reporting summarized one dataset in which HTML messages bounced 674% more often than plain text, while other large analyses found similar raw delivery. I treat that contrast as a warning against universal claims. The Mailtrap comparison shows why formatting and sender reputation need to be evaluated together.

Practical rule: I test inbox placement by format, audience segment, and mailbox provider. I don't use “delivered” as a synonym for “seen in the inbox.”

I also keep a separate deliverability checklist for authentication, suppression, complaints, and rendering. My process is documented in this email deliverability testing workflow. The format matters, but it can't rescue a neglected list or a weak sending setup.

Reader Perception, Trust, and Accessibility

Plain text changes the social meaning of a newsletter. When I send a text-only issue, readers often treat it like a note rather than a publication. The response is more conversational. They answer a question, challenge an opinion, or send a quick detail without feeling that they're entering a funnel.

That tone can help independent operators build trust, but it has limits. A long text dump can become difficult to follow, especially when the issue contains multiple stories, sponsor disclosures, or instructions. Plain text is low-friction, not automatically well-designed.

Accessibility makes the decision more serious. A 2026 Stripo analysis reported that only 0.11% of 443,585 tested HTML emails met WCAG accessibility criteria, as summarized by Mailwarm's accessibility coverage. I don't treat that as proof that HTML is inaccessible. I treat it as evidence that teams aren't testing or building HTML carefully enough.

Plain text isn't the whole accessibility solution

Screen readers can handle plain text, but readers still need clear sequencing, useful link labels, and understandable writing. A text email with a wall of URLs isn't considerate. Neither is an HTML email that hides the important sentence in an image, relies on color alone, or uses decorative markup that confuses navigation.

For HTML, I use live text, meaningful headings, descriptive links, sufficient contrast, and sensible reading order. I also check the message with images disabled. The email should still explain what matters without forcing the reader to reconstruct the design.

Sponsorships create another practical constraint. A sponsor may need a logo, a defined placement, a call-to-action button, or a visual product block. Plain text can satisfy some of that with careful copy, but structured HTML usually gives me a clearer commercial unit and a more predictable presentation.

The trade-off is trust. A sponsor block that dominates the issue makes a personal newsletter feel like an ad vehicle. I keep the editorial message useful even when the email contains paid placements.

The accessible choice is the version that preserves meaning, navigation, and action for the widest range of readers. That may be plain text, or it may be carefully built HTML.

Production Workflows and Platform Experiences

The key difference between plain text and HTML appears in the production calendar. I can draft plain text, add links, send a test, and revise the copy without thinking about columns or mobile breakpoints. HTML requires a second pass for spacing, image behavior, button rendering, and client-specific quirks.

I use LetterBucket for my primary newsletter because its multipart handling fits the way I send issues. Its editor is straightforward for simple layouts, but I find it restrictive when I want a custom sponsor module or an unusual content block. That limitation is useful when I need consistency, and annoying when I want control.

How I use each platform

I also test beehiiv and Substack because platform workflow changes the format decision.

• LetterBucket: I'd choose it for an operator who wants a focused newsletter workflow and dependable multipart sending. The downside is the editor's limits for highly custom layouts.
• beehiiv: I'd choose it for a creator prioritizing growth mechanics and monetization experiments. I find the broader publishing workflow useful, but the extra controls can make a simple issue feel more operational than editorial.
• Substack: I'd choose it for someone who wants a low-friction publishing and paid-subscription setup. I wouldn't pick it when deep design control or a bespoke email system is central to the business.

I don't recommend a platform from its template gallery. I set up the same issue, inspect the plain-text alternative, send previews, and review the mobile result. I also check whether the editor preserves links, headings, and fallback content after I make revisions.

For a wider platform comparison, I keep my notes in this newsletter software guide. The important question is who owns the workflow. If I need to move subscribers, change templates, or add sponsorship operations, a pretty composer doesn't tell me enough.

The hidden cost of HTML

HTML work expands when more people touch the issue. A writer edits the copy, a designer adjusts the layout, and someone else checks the final render. Plain text reduces those handoffs. That doesn't make it automatically better, but it does make the publishing system easier to maintain.

I also keep a version of every issue in a plain editor before pasting it into the platform. Some visual editors alter spacing or convert links unexpectedly. The workaround is boring, but effective. I preserve the source copy, compare the rendered preview, and send a controlled test before publishing.

A Practical Multipart Strategy

I stopped choosing one format for every recipient. I now send a multipart/alternative email containing both an HTML part and a real text/plain part. The recipient's email client can display the version it supports, while I retain the structure and branding needed for the main newsletter.

The key detail is “real.” I don't let the platform generate a useless fallback filled with broken spacing, missing links, or image filenames. I write the plain-text version as a readable message in its own right.

My setup sequence

1. Write the editorial copy first. I define the lead, supporting links, sponsor disclosure, and primary action before touching the template.
2. Build the HTML around that copy. I use live text, clear hierarchy, descriptive links, and restrained styling.
3. Create the text part separately. I remove decorative elements, preserve the order of ideas, and write link labels that make sense without buttons.
4. Check the MIME setting. In LetterBucket, I verify that the send includes both alternatives rather than treating plain text as an afterthought.
5. Preview both outputs. I open the HTML version with images disabled and inspect the plain-text source in a client that displays it directly.
6. Send internal tests. I check desktop and mobile rendering, link destinations, line wrapping, and the sponsor block before scheduling.

One recurring annoyance comes from HTML editors that regenerate the text alternative after I edit a button or content block. That process can strip deliberate line breaks and turn a clean message into a dense paragraph. I always inspect the final text part after the last visual edit.

What I measure

Multipart doesn't give me identical experiences across every mailbox. Some readers will see HTML, others will see text, and some clients may alter the presentation. I therefore compare clicks, replies, complaints, and qualitative feedback instead of treating one open metric as the verdict.

Build one message, then give readers two sensible ways to read it. That's more durable than forcing every subscriber into the same presentation.

This setup also protects the content when images fail. A reader can still understand the issue, follow a labeled link, and reply. HTML handles the visual job. Plain text protects the message.

When to Choose Plain Text and When to Use HTML

I choose plain text when the newsletter's value is the writer's point of view and the desired response is conversation. Founder notes, operational lessons, personal essays, and community updates usually work well without a designed shell. The reader can move quickly from the opening sentence to the reply box.

I choose HTML when the information benefits from layout. Product comparisons, event details, visual data, sponsor packages, and multi-story digests need hierarchy that plain text struggles to provide. I keep the design restrained because excessive decoration can lower engagement, as HubSpot reported in its testing, where simpler messages performed better and plain text performed best. The findings are available in HubSpot's plain-text email testing report.

My decision test

I ask four questions before choosing:

• Is a reply the main conversion? I use plain text or very light HTML.
• Does the reader need to scan several content blocks? I use structured HTML.
• Does a sponsor require visual presentation? I use HTML, while keeping the editorial content prominent.
• Can I test and maintain the template properly? If not, I simplify the design or send plain text.

List size alone doesn't decide this for me. A small paid newsletter may need polished HTML because subscribers expect a publication. A large founder-led list may perform better with a personal note. Monetization stage matters more than subscriber count. Early on, I prioritize writing speed and replies. Once sponsorships or visual products become material, I accept the production cost of HTML.

My personal default is multipart with restrained HTML and a carefully written plain-text alternative. For a conversation-first newsletter, I may make plain text the primary editorial experience. For a sponsor-supported publication, I choose simple HTML and protect the text version instead of pretending the design isn't part of the business model.

Choose one recent newsletter issue and rebuild it in both formats today. Send each version to your internal test addresses, inspect the plain-text alternative, disable images in the HTML version, and record replies, clicks, complaints, and rendering problems. For more practical experiments on growing and monetizing a newsletter, subscribe to Grow and monetize your newsletter.