Email preview text: what it is and how long it should be
Preview text, also called a preheader, is the short line that appears after or under the subject line in the inbox. Aim for 40 to 90 characters: phones show roughly the first 40, and wider layouts show more. Use it to add a second reason to open, never to repeat the subject, and always set it. If you don't, the inbox fills it with the first text it finds in your email, which is often "View in browser".
Where preview text comes from
Inboxes show the first text in your email's HTML after the subject. Email platforms let you set that text directly, usually in a field called Preview text or Preheader. Behind the scenes, it's placed at the top of the email in a hidden block, so subscribers see it in the inbox but not in the email itself.
If you leave the field empty, the inbox grabs whatever comes first: "View in browser", your logo's alt text, or the start of a navigation bar. That wastes the second most valuable line you have.
How much each inbox shows
There's no fixed character count. It depends on the screen width, the font, the reader's settings and how long your subject line is. As a rough guide at common screen sizes:
| Inbox | Layout | Roughly visible |
|---|---|---|
| Gmail, phone | One line under the subject | about 40 characters |
| iPhone Mail | Two lines under the subject | about 80 to 90 characters |
| Outlook, desktop list | One line under the subject | about 40 to 50 characters |
| Gmail, desktop | Same line as the subject | whatever fits after the subject |
On Gmail desktop, subject and preview text share one line, so a long subject leaves little room. That's one more reason to keep subjects short.
How to write it
- Complement the subject. If the subject is the headline, the preview text is the subhead. "Last chance: 20% off every dry bag" pairs well with "Ends tonight at midnight. Free shipping over $50."
- Front-load it. Put the most useful words in the first 40 characters, since that's all many phone readers see.
- Don't repeat the subject. Repeating it wastes the space and reads as lazy.
- Set a fallback for merge tags. "{{first_name}}, your picks are here" becomes ", your picks are here" for anyone without a name on file. Every email platform lets you set a default value.
- Skip the clickbait. A preview that doesn't match the email hurts trust and future open rates.
When preview text is too short
If your preview text is shorter than the space available, some inboxes fill the rest of the line with the start of your email body. To stop that, add invisible spacer characters right after the preview text in your HTML:
<div style="display:none;max-height:0;overflow:hidden;"> Your preview text here </div> <div style="display:none;max-height:0;overflow:hidden;"> ͏‌ ͏‌ ͏‌ (repeat 20 to 30 times) </div>
Most email platforms add the first block for you when you fill in the preview text field. You only need the second.
Test before you send
- Check the subject and preview text together on a phone and on desktop.
- Check dark mode. Light gray text can disappear on a dark background.
- Send one test to an address with no first name on file to see your fallback.