Preheader text: the line most senders waste
The preheader is a second subject line you get for free — and half of all senders ship “View this email in your browser” in it.
Writing · 2 min read · updated
What it is and where it comes from
The preheader (or preview text) is the snippet a mail client shows after the subject line in the inbox list. It is not a separate field in the email standard — the client simply takes the first text it finds in the body. If you do not choose that text deliberately, the client chooses for you.
Which is how half the newsletters in your inbox introduce themselves with “View this email in your browser”, “Unsubscribe”, or a fragment of a menu. Prime inbox real estate, spent on plumbing.
Write it as the subject's second half
Subject and preheader render as one line of pitch, so write them as one unit: the subject makes a specific promise, the preheader adds the detail that tips the open. Not a repeat of the subject — the client is already showing the subject an inch to the left.
- Complete, don't repeat. Subject “Your March report is ready” + preheader “Opens are up 12% — one campaign did most of it” works. The same subject twice wastes the space.
- Front-load, again. Clients show anywhere from ~35 to ~90 characters depending on device and window width. The payload goes first; assume everything after character 40 may not exist.
- No “can't see this email?” housekeeping. The view-in-browser link can live in the body. It just cannot be the first text in it.
The technical bit
The standard implementation is a div at the very top of the body, styled invisible (zero height, hidden overflow), often followed by whitespace characters to stop the client pulling visible body text into the leftover space. Every reputable template supports this; it is not a trick, and it has no deliverability cost.
Test in real clients before trusting it: Gmail, Apple Mail and Outlook each truncate differently, and some clients ignore the hidden div on plain-text-heavy messages.
A checklist worth thirty seconds per send
- Preheader set deliberately, not inherited from the template.
- Reads as a continuation of the subject, not an echo of it.
- Payload inside the first 40 characters.
- No unsubscribe, view-in-browser or menu text leaking in.
- Checked on a phone, where truncation is harshest.
Common questions
How long should preheader text be?
Write 40–90 characters and put the substance in the first 40. Longer text is fine — clients truncate gracefully — but nothing important should live past the fold.
Does the preheader affect deliverability?
Not directly — it is ordinary body text to a filter. Its effect is on opens, which is indirect and real: it is the third thing a reader sees after sender name and subject.
Is hiding the preheader div considered deceptive?
No. It is a rendering convention, universally used, and the text it hides is shown to the reader in the inbox list — the opposite of hiding content.
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