Don't Let A Great Hook Get Cut Off

Test your newsletter subject line and preheader text exactly as they appear in your subscribers' mobile and desktop inboxes. Optimize for character limits, spark curiosity, and get higher open rates across every platform.

Draft Your Hook

15 chars
42 chars (Aim for < 40 on mobile)
53 chars

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iOS Mail (iPhone)
Your Newsletter
How to write hooks that finally get clicks
Plus 3 proven templates to boost your open rate today.
9:41 AM
Gmail (Desktop)
Your Newsletter
How to write hooks that finally get clicks - Plus 3 proven templates to boost your open rate today.
May 14

The Science of the Inbox: Subject Line Best Practices

Why Mobile Optimization Matters

With over 60% of all emails now opened on mobile devices, the visual real estate you have to capture your audience's attention has drastically shrunk. Desktop email clients might forgive a rambling subject line, giving you up to 80 characters of display space. Mobile devices, however, are ruthless. The standard iPhone mail app, Gmail app for Android, and mobile web clients typically truncate subject lines at around 40 to 50 characters, depending on screen width and portrait orientation.

When a subject line gets cut off, the underlying context of your message can be lost. Even worse, unintended truncation can completely alter the meaning of a sentence, leading to confusion or an immediate swipe to the trash bin. Our Subject Line Sandbox helps you identify exactly where the "fold" is for your text.

Mastering the Preheader Text

Preheader text is the unsung hero of email marketing. It operates as the secondary hook. If your subject line grabs attention, the preheader seals the deal by providing context and building anticipation. You should treat the preheader as a direct continuation of your subject line.

A common mistake marketers make is leaving the preheader blank, forcing the email client to crawl the body of the email and display utilitarian text like "View this email in your browser" or "Unsubscribe." This completely wastes valuable inbox real estate. Instead, craft a narrative: if your subject line asks a question, let the preheader tease the answer. Depending on the length of your subject line, popular devices might show anywhere from 40 to 100 characters of preheader text.

Three Formulas for High Open Rates

  • The Curiosity Gap: "The real reason your plants are dying." Provide just enough information to make them realize there is something they don't know, but must click to find out.
  • Direct Benefit: "Save 5 hours a week with this automation." Clean, clear, and perfectly tailored to a specific audience pain point. Keeps the most important metric (5 hours) at the very front to avoid truncation.
  • The Personal Question: "Are you making this rookie SEO mistake?" Questions naturally invite mental participation and compel the reader to verify if they are, in fact, making the mistake.

Front-Loading Your Value

Because you can never guarantee exactly how many characters every unique device will display, the ultimate rule of subject line composition is "Front-Loading." Put your most compelling words, your numbers, and your core value propositions in the first 30 characters. Everything that follows should be supplementary. An email that is designed to be skimmed in an inbox is an email that gets opened, read, and clicked.