Free Email Preheader Generator

Type your preheader text and get clean HTML with the hidden whitespace padding needed to stop body text from bleeding into your inbox preview.

Works across Gmail, Outlook, Yahoo, and Apple Mail.

Email Tester Inbox Placement Tester

Preheaders are a crucial yet often overlooked component of email marketing. They serve as a short summary that appears next to the subject line in the recipient's inbox, providing additional context and enticing the recipient to open the email. A well-crafted preheader, ideally around 140 characters or less, can significantly increase your email open rates and overall engagement. However, creating effective preheaders involves more than just writing compelling text. It's also essential to manage the technical aspects, such as adding the correct sequence of characters to ensure that your preheader is displayed correctly across various email clients. With the Email Preheader Optimizer, you can effortlessly create hidden preheaders that not only captivate your audience but also maintain the necessary formatting and character sequences for optimal email performance.

To ensure your preheader works effectively, it should be added at the top of your HTML, just after the <body> tag.

Paste or Type in Your Preheader Text Below:
Built with ♥ by Henry Timmes · Named contributor to RFC 7489 (DMARC)

What Is an Email Preheader and Why Does It Matter?

Before anyone opens your email, they see three things in their inbox: the sender name, the subject line, and the preheader. The preheader is that short line of gray text that appears next to or below the subject. Most email clients pull it from the first readable text they find in your HTML body, which means if you don't set one deliberately, your inbox preview fills up with "View this email in your browser," navigation links, or the opening line of your email copy ripped out of context.

A good preheader extends the subject line's message or adds a second hook. A broken one quietly suppresses your open rate on every send.

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The Third Inbox Signal

Recipients make open decisions in under two seconds. The sender name, subject line, and preheader are the only signals they have. Missing the preheader wastes one of three chances to earn that click.

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Prevent Preview Bleed

Without hidden filler characters after your preheader text, email clients keep pulling in body text until they fill the preview space. This tool appends invisible Unicode padding that blocks anything else from showing up.

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Works Across All Clients

The generated HTML uses the correct inline style attributes and character sequences tested across Gmail, Outlook, Yahoo, Apple Mail, and mobile clients so the preheader displays correctly everywhere.

Preheader Character Limits by Client

Email Client Mobile Preview Desktop Preview
Gmail ~55 characters ~90 characters
Apple Mail ~75 characters ~140 characters
Outlook ~40 characters ~75 characters
Yahoo Mail ~50 characters ~80 characters
Samsung Mail ~45 characters N/A

Best practice: Keep your preheader between 85 and 100 characters. That length shows meaningfully across mobile and desktop without getting cut off on any major client. Write it to complement your subject line, not repeat it.

Frequently Asked Questions

An email preheader is a short line of text that appears next to or below the subject line in most email clients before the recipient opens the message. It comes from the first readable text in your email's HTML body. A well-written preheader gives recipients extra context and can meaningfully increase open rates.

Most email clients display between 35 and 140 characters depending on the device and screen size. Mobile clients typically show around 40 to 70 characters. A safe target is 85 to 100 characters so the important part shows across all clients without getting cut off.

When you don't include a preheader, email clients grab the first readable text in your HTML body to fill the preview space. This often surfaces navigation links, "View in browser" notices, unsubscribe copy, or the first line of your email out of context. A preheader with hidden filler characters after it stops this from happening.

After your visible preheader text, the tool appends a string of invisible Unicode characters including zero-width non-breaking spaces. These fill the remaining character space that email clients allocate for the preview line. Without them, the client keeps pulling in body text until the preview is full.

Place the preheader code immediately after the opening <body> tag, before any other visible content. This ensures email clients read it as the first text in the message and use it for the inbox preview. Putting it anywhere else in the HTML can cause unpredictable preview behavior.

Yes. The preheader is one of three pieces of text a recipient sees before deciding whether to open: sender name, subject line, and preheader. A relevant preheader that extends the subject's message or adds urgency can lift open rates. One that shows "View in browser" or navigation links hurts them. It's the most consistently underused lever in email marketing.

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