Go and look at your inbox right now. Not the emails — the snippets. The grey text sitting next to each subject line.
Somewhere in there you'll find at least one that says "View this email in your browser." Possibly "Having trouble viewing this email? Click here." Maybe a string of unsubscribe links, or "Hi there, I hope this finds you well."
Every one of those is a sender who had a free line of inbox real estate and handed it back. Worse — each one broadcasts this is a generic marketing email before anyone has opened anything.
Preview text is the third most visible element in the inbox, after the sender name and the subject line. It takes about thirty seconds to set. Almost nobody sets it.
The short version
Preview text isn't a second subject line. It's a supporting argument.
The subject line creates interest. The preview text confirms it's worth acting on. Watch what happens when they work together:
Subject: "We changed one thing in our welcome email"
Preview: "(it added $1,200/month in revenue — here's the exact change)"
The subject line opens a curiosity gap. The preview text makes that gap irresistible by dropping in one concrete detail. Separately, either would have performed fine. Together they compound.
Know your character limits
Different clients show different amounts, which is why the front of the line matters more than the back.
| Client | Roughly what's visible |
|---|---|
| Gmail | 90–100 characters |
| Apple Mail | 75–90 characters |
| Outlook (mobile) | 35–50 characters |
| Outlook (desktop) | More than mobile |
The practical rule: keep the whole thing under 90 characters, and put the essential payload in the first 40. Outlook mobile may show you nothing beyond that, so a preview line whose punchline arrives at character 70 is a preview line that half your audience never sees.
Four strategies that work
1. Extend the subject line
Continue the thought as if it were one sentence broken across two lines.
| Subject line | Preview text |
|---|---|
| "The email I almost didn't send" | "…ended up being our highest-converting email all quarter." |
| "Stop sending emails on Tuesday" | "We tested every day for 12 weeks. The winner surprised us." |
2. Add a specific detail
Use it to drop in a concrete data point, name, or specificity the subject line deliberately left out.
| Subject line | Preview text |
|---|---|
| "How she tripled her click rate" | "Sarah runs a 4,000-person list. One CTA change did it." |
| "Your free email audit checklist" | "80 points. Takes 15 minutes. Catches everything." |
3. Answer the objection
Address the reason someone wouldn't open, right where they're deciding.
| Subject line | Preview text |
|---|---|
| "The 5-email welcome sequence" | "Copy-paste ready. Under 10 minutes to set up." |
| "I want to sell you something" | "But first, here's why it's worth your time." |
That second one is worth pausing on. It works precisely because it names the objection out loud instead of hoping the reader won't notice.
4. Create a second curiosity layer
Introduce a new curiosity element that compounds with the first.
| Subject line | Preview text |
|---|---|
| "My biggest email mistake this year" | "Hint: it had nothing to do with subject lines." |
| "The revenue you're leaving in your welcome flow" | "Most senders stop at email 2. The money is in email 5." |
The one thing none of these do: repeat the subject line. If your preview text restates what's already visible, you've used the space without spending it.
The technical bit
Most ESPs have a dedicated Preview text or Preheader field. Use it. That's the whole job.
If yours doesn't, you can do it manually. Add a hidden preheader at the very top of your email HTML:
<div style="display:none;max-height:0;overflow:hidden;">Your preview text here</div>
Then follow it with non-breaking space characters — ‌ repeated 50 to 80 times — to stop the actual body copy from leaking into the preview after your text ends. Without that padding, your carefully written line gets followed by "Hi there," or a stray alt-text fragment, which rather undoes the effect.
Then test. Send yourself a proof to Gmail, Apple Mail, and Outlook before it goes to the list, and confirm it displays cleanly in all three.
The pre-send checklist
Before any email goes out:
- Preview text is set intentionally, not defaulting to "View in browser"
- It complements the subject line rather than repeating it
- It adds specificity, detail, an objection-answer, or a second curiosity layer
- The essential payload sits in the first ~40 characters
- The whole thing is under 90 characters
- Tested in Gmail, Apple Mail, and Outlook
Frequently asked questions
What is email preview text?
The snippet displayed after or below the subject line in an inbox list view, also called preheader text. It's the third most visible element in the inbox after the sender name and subject line. When it isn't set deliberately, email clients pull whatever text comes first in your HTML — usually "View this email in your browser" or a navigation link.
How long should preview text be?
Under 90 characters, with the essential payload in the first 40. Gmail shows roughly 90 to 100 characters, Apple Mail 75 to 90, and Outlook on mobile as little as 35 to 50 — so anything important that sits past character 40 will be invisible to a meaningful share of your audience.
What happens if I don't set preview text?
The email client pulls the first text it finds in your HTML. That's typically a "view in browser" link, an unsubscribe row, image alt text, or a generic greeting. Beyond wasting the space, it actively signals that this is a templated marketing email, which is exactly the impression you don't want at the moment someone is deciding whether to open.
What to do next
Open your ESP and look at your last five sends. How many had preview text set deliberately?
If the answer is "none," you've just found the cheapest improvement available to you. It's one field, thirty seconds, and it works on every email you send from here on.
Free: The subject line swipe file — formulas organised by framework, with matching preview lines.
Go deeper: The Email Copywriting Playbook — the full framework library and the 13-point pre-send audit.
Related guides
- Email subject line formulas — the line preview text supports
- Email copywriting: the complete system — the whole chain, from sender name to P.S.
- How to stay out of the Gmail Promotions tab — the other half of inbox visibility
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Written by
Muhammad Basim
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