Email Preheader Text: How to Write Previews That Boost Open Rates
The 85-Character Opportunity Most Email Marketers Ignore: Email Preheader Text
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Open your email app and look at your inbox. Every email shows three pieces of information before you decide to open it: the sender name, the subject line, and a short preview — the email preheader text. Most email marketers spend significant time crafting subject lines. Almost none spend equivalent attention on the preheader, despite it being the second most visible piece of inbox real estate before the open.
Preheader text is the snippet of text displayed after the subject line in most email clients. In Gmail on desktop, it shows approximately 85-110 characters. On iOS Mail, it shows 30-65 characters depending on font size settings. On Android Gmail, the display can vary but is generally in the 50-90 character range.
This preview text is either manually set by the email sender or automatically pulled from the first text content in the email body. When not manually set, the preview often shows: "View this email in your browser | If you can't see this email..." or — worse — "![email image]" or random HTML artifacts that make your email look broken.
The practical upside: if your competitors aren't optimizing preheader text, simply doing it well gives you a meaningful inbox advantage. Research suggests that optimized preheader text can increase open rates by 7-15% by making the subject line + preview combination more compelling as a pair.
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How Preheader Text Works Technically ve Email Preheader Text
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Most email platforms — Mailchimp, Klaviyo, ActiveCampaign, HubSpot — have a dedicated preheader text field in their campaign editor. Text entered here is inserted at the very beginning of the email's HTML body in a hidden div with styling that makes it invisible within the email itself but visible to email clients that display preview text.
The HTML typically looks like this:
<div style="display:none; max-height:0; overflow:hidden; mso-hide:all; font-size:1px; color:#fff; line-height:1px; opacity:0;"> Your preheader text goes here. </div>
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This hidden div is the first text content in the email body, so email clients that pull preview text from the email body (rather than a dedicated preheader field) will display it as the preview.
If your email platform doesn't have a preheader field, you can manually add this HTML snippet at the very beginning of your email body template. Ensure the styling keeps it invisible within the email itself while remaining readable as preview text.
One additional technique: pad your preheader text with non-breaking spaces ( ) or zero-width non-breaking spaces at the end to prevent email clients from pulling text from your email body after the preheader ends. Without this padding, some clients will append body text to your preheader, creating a concatenated preview that wasn't intended.
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The Subject Line and Preheader as a Pair
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The subject line and preheader text should work together as a unit. Thinking of them separately misses the point — the subscriber reads them together in under a second while deciding whether to open.
There are four effective relationship patterns between subject lines and preheader text:
Completion. The preheader finishes a thought started in the subject line. Subject: "We analyzed 1,000 email campaigns..." | Preheader: "...and found this one thing in common among the top performers." The ellipsis creates an irresistible pull to open and complete the sentence.
Elaboration. The preheader adds specific detail to a general subject line. Subject: "Your email open rates are dropping." | Preheader: "Here are the 3 reasons we identified — and how to fix each one this week." The subject line creates relevance; the preheader makes the value proposition concrete.
Reinforcement. The preheader repeats the subject line's core message in different words, reinforcing the value from a different angle. Subject: "How to double your email list in 30 days" | Preheader: "The exact 5-step system our clients use to add 1,000+ subscribers per month." The subject line makes the promise; the preheader makes it credible.
Curiosity amplification. The preheader deepens the curiosity created by the subject line. Subject: "Don't send another email until you read this" | Preheader: "One setting in your ESP that most marketers have wrong — and it's costing them deliverability." The subject line demands attention; the preheader rewards stopping to read.
The pattern that consistently underperforms: preheader text that simply repeats the subject line or summarizes it in slightly different words. Repetition uses the preheader space without adding any incremental reason to open.
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Writing Preheader Text: Principles and Examples
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Principle 1: Never waste the space on logistics.
The worst common preheader texts are "View this email in your browser" or "To unsubscribe, click here." These administrative messages appear as the preview when the email platform generates them from body content and there's no explicit preheader set. They actively hurt open rates — subscribers see administrative copy and assume the email is procedural, not valuable.
Principle 2: Lead with the most compelling element.
The first 30-40 characters of your preheader are the most visible, particularly on mobile where preview text is truncated more aggressively. Put your most engaging word or concept first. Don't bury the hook at the end of a long setup sentence.
Principle 3: Match tone to your audience.
Preheader text should feel like your brand voice. If your email program is known for being direct and practical, a preheader that's whimsical or pun-heavy creates dissonance. Consistency between your brand voice and every inbox touchpoint builds recognition and trust.
Principle 4: Use specific numbers and details.
"5 tactics that saved us 3 hours per week" outperforms "some useful email marketing tips" in the same character count. Specificity signals credibility and makes the promised value feel concrete and real.
Principle 5: Create genuine urgency or scarcity when appropriate.
"Offer ends at midnight" or "Only 12 spots remaining" are legitimate urgency signals when they're true. They dramatically increase open rates for promotional emails when the deadline or scarcity is genuine. Fabricated urgency trains subscribers to ignore future urgency claims and erodes trust.
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Character Length and Display Optimization
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Getting preheader length right matters because truncation — where the email client cuts off your text mid-sentence — can undermine your entire message.
Desktop Gmail displays approximately 85-110 characters of preheader text alongside subject lines. On mobile Gmail, you get roughly 50-70 characters. iOS Mail in default settings shows about 30-65 characters. Given this variability, the safest strategy is to front-load your most important content within the first 40-50 characters and use the remainder for supplementary detail.
Write your preheader at a length that creates a complete thought within 40-50 characters, then extend to 85-100 characters with additional value if the core message holds up in either length. Test your preheader at different truncation points by resizing your email preview or checking specific device previews.
Avoid ending your preheader on an orphaned word or mid-thought. "Learn the 5 email marketing mistakes that are..." appearing as the preview leaves the subscriber hanging — which can work as a curiosity hook, but is more often just frustrating. Test your specific truncation carefully.
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A/B Testing Your Preheader Text
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Preheader text is an underutilized A/B testing opportunity. Because it works in combination with the subject line, testing preheader variants for the same subject line isolates the preheader's contribution to open rate.
Run tests comparing:
Completion versus elaboration relationship styles for the same subject line
With specific numbers versus without (general statement)
Longer (85+ characters) versus shorter (40-50 characters)
Different emotional angles: practical ("here's how to") versus curiosity ("this surprised us")
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For A/B tests to be statistically meaningful, you need a sufficient list size. A minimum of 1,000 recipients per variant is generally recommended to achieve statistical significance on open rate differences. For smaller lists, collect data across multiple campaigns before drawing conclusions.
Track the downstream metric — click-through rate — in addition to open rate. A preheader that dramatically increases opens by creating a curiosity gap that the email doesn't fulfill will show high open rates but low CTR and potentially elevated unsubscribe rates. A winning preheader lifts both open rate and click-through rate.
Document your test results in a shared reference document. Over time, you'll accumulate data on which preheader approaches work specifically for your audience — information that's more valuable than general industry benchmarks.
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Common Preheader Text Mistakes
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Duplicating the subject line. If your subject line reads "How to improve your email open rates" and your preheader reads "Tips for increasing email open rates," you've used the combined real estate to say the same thing twice. The preheader should add, not repeat.
Being too vague. "We have exciting news for you!" or "Something special is coming..." feel like lazy teases that signal filler content rather than genuine value. Modern subscribers are savvy about empty hype language and mentally filter it as spam.
Forgetting to set it at all. This remains surprisingly common and results in "View in browser" or body content artifacts appearing as preview text. Every campaign should have an intentionally written preheader.
Making it too long with no truncation testing. Writing 200 characters of preheader text hoping the whole message comes through — without testing how it truncates — often results in an awkward mid-sentence cutoff that communicates nothing useful.
At Blakfy, we treat preheader text as part of our standard subject line review in every email audit — because it's one of the fastest and lowest-effort improvements available for open rate performance.
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Frequently Asked Questions
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How long should preheader text be?
Aim for 40-90 characters to ensure the full message is visible in most common email clients. Front-load your most important message within the first 40 characters to maintain impact even on devices with shorter preview displays. Use the additional characters up to 90 for elaboration rather than essential information.
Does preheader text affect email deliverability?
Not directly. Email deliverability is primarily influenced by sender reputation, authentication, and engagement rates — not preheader content. However, a compelling preheader increases open rates, and higher open rates are a positive engagement signal that indirectly improves deliverability by demonstrating to ISPs that your emails are wanted by recipients.
Should I use emoji in preheader text?
Emoji in preheader text can increase visual distinctiveness in the inbox, but the impact varies significantly by audience. B2B audiences tend to respond less positively to emoji in business communication contexts. B2C and lifestyle brands often see open rate improvements from single, relevant emoji used at the start of a preheader. Test with your specific audience before making emoji a standard practice.
