Email preheader: 9 tips for writing preview text

A preheader, also known as preview text, is the short line a recipient sees in the inbox next to the subject line or below it. A good preheader does not repeat the subject line, it adds to it: it tells people what they will find in the email, finishes the thought the subject line started and gives them one more reason to open. In Quanda it is limited to 50 characters, so the essential part goes first. Below you will find 9 tips for writing a preheader, examples of subject line and preheader pairs, an overview of how much of it recipients see in different inboxes, and how to set it up in Quanda.

Key takeaways

1. The preheader is the second line people use to decide whether to open an email. In Quanda's 2017 survey, 14 % of people look first at the preheader, 30 % at the subject line and 56 % at the sender.
2. The inbox pads a short preheader with more text from the email. Quanda does not insert any filler after it, so use as much of the 50 characters as you can.
3. Litmus recommends keeping preview text under 90 characters. Inboxes show anything from no lines at all to five, which is roughly 278 characters.
4. The preheaders that work best finish the subject line, clarify the content or add a call to action.
5. Test the subject line and preheader together in a campaign with A/B testing.

In short: what a preheader is, how long it should be, where to set it and what happens without one

• What it is: a short line next to or below the subject line in the inbox. It supports the subject line rather than repeating it.
• How long: up to 50 characters in Quanda, with the key words at the start.
• Where to set it: in Quanda's email editor, in the line above the email where you can type the preheader.
• What happens without one: the inbox shows the first text in the email, typically the view in browser link.

What has changed since this article was first published: The original tips still hold today, I have just added examples. New in this version: an overview of how much of the preheader Gmail, Apple Mail and Outlook show, what happens when the preheader is short or missing, how to set it up in Quanda, and a more recent development: some inboxes now show an AI summary of the email instead of the preheader.

What is an email preheader

A preheader is the short text that appears in the inbox right next to the email's subject line or below it, before the recipient opens the email. It is also known as preview text. Every inbox has its own name for it: Gmail calls it a snippet, Apple Mail a preview and Outlook a message preview. The principle is the same everywhere.

Think of it as a second subject line. That is why the same rules apply to it as to the email subject line: it should be specific, honest and tell the recipient what they will get out of the email. Unlike the subject line, though, it can take a bit more. It is a good place to experiment with humor, symbols or other tactics that are not really suitable for the subject line itself.

Why the preheader matters

Together with the sender's name and address and the subject line, the preheader is the first thing your recipient sees and uses to decide whether to open your email. In our survey, we asked email recipients what they look at first when deciding whether to open an email.

So the preheader comes third. That does not make it unimportant. The sender and the subject line make people stop, and the preheader often gives them the final reason to actually open the email. It is also the only one of the three that many companies leave empty.

How many characters of the preheader recipients see

How many characters of the preheader a recipient sees depends on the inbox, the device and the settings. According to Litmus, anything from zero to five lines can be shown, which is roughly 278 characters. So there is no fixed limit, only safe boundaries.

Sources: Litmus, The Ultimate Guide to Email Preview Text (2024); Apple, iPhone User Guide and Mail User Guide for Mac; Microsoft 365 Roadmap 564610. As of October 2026.

That leads to a simple rule: the essentials belong in the first few words. Quanda's 50 character limit takes you there on its own. That way the whole preheader fits even into a narrow preview on mobile. Where the inbox shows more lines, it adds the beginning of the email after it.

Tip: The most reliable check is a test email. Send one from the Sending step to your own inbox on both mobile and desktop, and you will see the subject line and preheader exactly as your recipients will. The steps are described in the help article Setting up mailing in a simple campaign.

9 tips for writing an email preheader

The preheader is there to hint at what the email is about and nudge the recipient to open it. Add useful information or specific details about the content of the email. The following nine tips will help you do that.

1. Keep it short, lead with the main point

The preheader should be short and to the point so it displays properly in different email clients. That is why Quanda limits it to 50 characters. Put the key words first so they stay visible even where the inbox cuts the preheader short.

2. Summarize or clarify the content

Briefly sum up the content of the whole email and spell out what your message is about. If your subject line says a spring sale is on, the preheader can specify which products the offer covers.

• Subject line: "Our spring sale starts now"
• Preheader: "30 % off bikes, helmets and cycling glasses"

3. Follow on from the subject line

The preheader can round off or extend the subject line. Whatever you start in the subject line, you can finish in the preheader, because the two are usually shown side by side or one below the other.

• Subject line: "Are your open rates dropping?"
• Preheader: "The three most common causes and how to fix them"

4. Add a call to action

If the email has a call to action further down, you can place the first one right in the preheader. Short phrases like "Read more", "Pick a date" or "Find out more" work well. Even better is a call to action that says what the recipient gets: "Book your seat by Friday".

5. Don't be afraid of humor

You can also put something witty or playful in the preheader, depending on the content of the message you are sending. The preheader can take more than the subject line because it is less exposed. The same goes for symbols and emoji: one well-chosen symbol helps, but more of them eat into your 50 characters and do not display the same way in every email client.

6. Don't repeat the subject line or the heading

Watch out for repetition. It can be tempting to reuse the subject line or the main heading of the email as the preheader, but be more creative. Use this space to encourage recipients to open the email.

• Weak: subject line "New in our shop", preheader "New in our shop".
• Better: subject line "New in our shop", preheader "Three new shades and free shipping until Sunday".

7. Consider personalization

If personalization has worked for you in other parts of the email, try it in the preheader too. Only use the recipient's name if the name field is filled in correctly, and not in every campaign. How to create and insert a personalized salutation in Quanda is explained in the help article Personalization in campaigns.

8. Point out the most interesting thing inside

In the preheader you can mention an interesting link or article further down in the email and encourage the recipient to find it. For example: "Inside: a savings calculator for 2027".

9. No tricks

Just like everywhere else in the email, the preheader should not be worded to trick the recipient into opening the email. A fake "Re:", made-up urgency or a promise the email does not keep will lift your open rate once and damage trust for good.

Tip: Always write the subject line and the preheader together, as one sentence split into two parts. Read them out loud one after the other. If they make sense and do not repeat each other, you are done.

Subject line and preheader examples

Every preheader in the table is under 50 characters and none of them repeats the subject line. Each one adds information the subject line does not have: what exactly, when, how many or how long.

What happens if you leave the preheader empty

If you leave the preheader empty, the email client takes the first text it finds in the email. According to Litmus, that tends to be the View in browser link, image alt text or the start of the footer. The space that could have sold your email ends up filled with a sentence that says nothing.

The same can happen with a short preheader. When the preheader is shorter than the space the inbox has for the preview, the email client fills the rest with more text from the email. Quanda does not add invisible padding after the preheader, so your preheader may be followed in the inbox by, for example, the view in browser link or the first heading of the email. Two things help here:

• Use as much of the 50 characters as you can.
• Start the email with a heading that naturally follows on from the preheader. When the inbox adds it after the preheader, it will make sense.

How to set the preheader in Quanda

You set the preheader directly in the campaign's email editor:

1. Open the campaign and continue to the email editor.
2. Above the email itself, find the line where you can type the preheader. Next to it on the right is the link to view the email in a browser.
3. Click into the line and check in the right panel that the Show toggle is on. Then write your preheader, up to 50 characters.
4. Check that the preheader complements the subject line, which you write in the Email subject field above the editor.
5. In the Sending step, send yourself a test email and see how the subject line and preheader look in the inbox.

You can set the preheader in all types of email campaigns: in a simple campaign, an A/B testing campaign, a logic campaign, an email series and a birthday and name day campaign. You can insert a personalization tag, such as a salutation, and emoji into the preheader. The 50 character limit counts the text of the tag, not the name that replaces it when the email is sent.

The preheader line has its own settings in the right panel. The Show toggle turns the preheader on. When it is off, you cannot fill the preheader in. The Hide on mobile and Hide on PC options decide whether the recipient also sees the preheader after opening the email. With both turned on, the preheader is visible only in the inbox list together with the sender and the subject line, and it no longer appears in the opened email. In the panel you can also set the font, size and colour of the preheader.

Working in the editor is described in detail in the help article E-mail editor of a simple e-mail campaign. If you want to find out which preheader works better, use a campaign with A/B testing. In version B, change only the subject line and the preheader, keep the content the same and choose opens as the winning criterion. You will find the steps in the help article How to create and set up an e-mail campaign with A/B testing.

The preheader and AI summaries

Since 2024, some inboxes show an AI-generated summary instead of the first lines of an email.

• Apple Mail with Apple Intelligence turned on shows a short summary of the content under each unread email. This works in supported languages, English included, so English-speaking recipients who have it enabled see the summary in place of your preview text. Recipients can turn it off and go back to seeing the first lines of the message. As of October 2026, Apple Intelligence does not support Czech, Slovak or Polish.
• Yahoo Mail, according to Yahoo's announcement, has shown one-line email summaries in its mobile app since November 2024.

What does that mean for the preheader? Where a summary replaces the preheader, the content of the email decides. A subject line, preheader and first paragraph that all say the same thing give the AI the right material to work with. A misleading preheader, on the other hand, gets exposed by the summary before the recipient even opens the email.

Checklist before sending

Before you send your campaign, run the preheader through this checklist:

• The preheader is filled in and has no more than 50 characters.
• The most important words come first.
• The preheader complements the subject line and does not repeat it or the first heading of the email.
• The preheader says what the recipient will find in the email, or includes a call to action.
• If you use a salutation, the name is filled in correctly.
• The preheader does not promise more than the email delivers.
• The email starts with a heading that follows on from the preheader.
• You have checked the test email in your inbox on both mobile and desktop.

Final thoughts

A preheader takes a few minutes to write and is the cheapest way to give your subject line a boost. Always write it together with the subject line, check it in a test email and test it on important campaigns. The subject line itself is covered in detail in the article How to write an email subject line people actually open.

If you want to dig deeper into writing emails, take the free online course Email Copywriting and Design That Gets Read, whose first lesson is all about the subject line and the preheader. And if you are not sure how to write preheaders for your industry, get in touch. We will go through your recent campaigns with you and show you where there is room to improve.