Email Preheader Text: How to Improve Email Open and Engagement Rates

Right after your subject line, before a single word of your email body is visible, there’s a short strip of text quietly deciding whether your email gets opened or ignored. Most businesses leave it to chance.

What Preheader Text Actually Is

The preheader is the snippet of text that appears next to or beneath the subject line in an inbox preview. Left unconfigured, most email clients default to pulling the first visible line of your email — often something unhelpful like “View this email in your browser.”

Why It Deserves Deliberate Attention

Subject lines create curiosity; preheader text either reinforces or wastes it. A strong pairing works like a one-two punch — the subject line hooks attention, and the preheader adds the specific detail that pushes the open.

Best Practices for Writing Preheader Text

Complement, don’t repeat — If your subject line already states the offer, use the preheader to add specificity or urgency instead of restating it.

Keep it within 40–100 characters — Most inboxes truncate beyond this range, especially on mobile.

Avoid default fallback text — Always set custom preheader text; never let it default to your unsubscribe link or a stray HTML comment.

Test variations — Preheader copy is one of the easiest, lowest-effort A/B test elements available.

A Quick Example

Subject: “Your order shipped” paired with preheader “Arriving Thursday — track it live” gives far more reason to open than a repeated or blank preheader.

Key Takeaway

Preheader text is small but high-leverage — it costs nothing to optimize and directly influences open rates. Treat it as a required field in every campaign, not an optional afterthought.

Want to A/B test preheaders effortlessly? MDS’s email tools make preheader testing part of your standard campaign workflow.