Preview Text
Also known as: Preheader, Preview Snippet
Preview text (also called the preheader) is the short snippet of text visible next to or below the subject line in the inbox list. Most inbox clients render the first 50-100 characters of the email body as preview text by default. Setting a custom preview text via a hidden `<span>` or explicit preheader tag is a 5-15 percent open-rate lift on average.
The subject line gets all the attention. Preview text gets almost none. The gap is the opportunity.
What inbox clients show
- Gmail (web): subject line + first 60 chars of preview
- Gmail (mobile): subject line + first 80 chars of preview
- Outlook (desktop): subject line + first 60 chars
- Apple Mail (iOS): subject line + first 80 chars
- Outlook (mobile): subject line + first 50 chars
How to set custom preview text
Most ESPs (Mailchimp, Klaviyo, HubSpot) have a Preview Text field that injects a hidden span at the top of the email body. For senders without ESP-managed preview text:
```html <span style="display:none;font-size:0;color:#ffffff;line-height:0;"> Your custom preview text here. Up to ~80 characters. </span> ```
What to put there
- Continue the subject line's hook rather than repeating it
- Add specificity (numbers, dates, names) that subject line lacks
- Avoid pre-header litter ("View in browser" defaults look unprofessional)
- Match the opening line so the recipient sees coherent flow on open
Common mistakes
- Letting it default to the email's first line (often unsubscribe footer or "View in browser")
- Repeating the subject line verbatim
- Using emoji-only preview (gets stripped or rendered as bare unicode)
- Stuffing keywords (looks like spam)
Frequently asked questions
Does preview text affect deliverability?+
Indirectly. Better preview text lifts open rate, and open rate is one input to sender reputation. The mechanism is engagement, not preview text itself.
Should every email have custom preview text?+
Yes. Default preview text usually shows email-template scaffolding ('View in browser', alt text from headers) that looks unprofessional.
Put this concept into practice
Free tools, articles, and features on this same topic.
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We update these pages when the underlying mechanics change. new mailbox-provider rules, new tracker behavior, new measurement gaps. The dates above are real revisions, not auto-touches.