The email preview text length that survives an iPhone is shorter than you think
Two people on the same model of iPhone can read two different sentences from one campaign, and one of them stops mid-word.
A client asked why clicks had gone flat while opens held. It wasn't the subject line and it wasn't the offer. It was the preview text, which read as one clean sentence on desktop and stopped after four words on the phones most of the list had moved to. Here's how to write one that survives the cut.
Opens held, clicks went flat, and the preview was the fault
A client asked us why their open rates looked fine while clicks on the same campaigns had gone flat. Nothing had changed in the subject line. Nothing had changed in the offer. What had changed was where the list was reading: most of it had moved from laptop to phone, and nobody had ever looked at the preview text on a phone.
On desktop the preview read as one clean, persuasive sentence. On an iPhone it stopped after four words and left the fifth hanging mid-clause. They'd been shipping a broken sentence to most of their list for months and calling it a preview.
Rare mistake? Not remotely. It's the default outcome of writing preview text in a desktop email builder and never checking it anywhere else. Craft at this level is the unglamorous half of a properly run email programme.
No two email clients cut the preview in the same place
Apple Mail on iPhone shows somewhere between roughly 35 and 90 characters of preview text, and the number moves with the device and the orientation. It shifts again when the reader has your brand saved in their contacts, because the saved name eats into the space before the preview even starts. The same campaign can truncate in two places on the same model of iPhone. Same phone, different sentence.
Gmail on Android runs on different rules again, roomier in some layouts and tighter in others. Outlook on desktop is more generous than almost anything on mobile. There's no single safe length, so one line written once and pasted into every send is the wrong unit of work.
Stop asking whether the preview text is good. Ask what it does at 35 characters and whether it still does its job there. If it only works at 90, you've written a preview for desktop and hoped mobile would be kind. It usually isn't.
Write the preview as its own idea, not the subject's second half
The usual mistake starts with a subject line you're pleased with, then a preview bolted on as the second half of the same sentence. New arrivals just landed, says the subject, and they're going to sell out fast, says the preview. On a wide screen that's one punchy thought. On an iPhone it dies mid-clause with no verb landing anywhere.
The preview has to stand as a short, complete idea inside the first handful of words, because that's genuinely all some of your readers will see. It doesn't need to repeat the subject line. Its opening chunk just has to carry weight on its own, and whatever comes after the cut is a bonus for readers on more generous clients.
So ask one question every time you build a campaign: what must this preview say if it's cut after four or five words? Write that part first. Then extend the sentence for the people who'll see more of it, and never write the whole thing hoping the important bit happens to land early.
One subject line, two previews, and only one survives the cut
Wrong: the subject says your cart is waiting, and the preview says we noticed you left something behind and wanted to check if you had any questions. On a phone that cuts at 35 characters, that reads as we noticed you left something be. It repeats the subject, then ends on a non-word.
Right: the same subject, with a preview that says free delivery if you finish in the next hour. Cut at 35 characters it's still a coherent, motivating fragment, because the offer and the deadline both land before the cut. The rest is spare.
Same subject line both times. Only the preview changed. Test the pair properly before you crown either one, because a winner called on a small split proves nothing.
Then run the same test on every send. Highlight the first 35 characters of your intended preview and read only that back as if it were the whole thing. If it trails off mid-word or mid-clause, move the key information earlier in the sentence instead of writing around the cut.
Your Klaviyo reporting already knows how much room you have
Every list has a different mix of email clients, and that mix sits in your own reporting, not in a general best-practice article. Klaviyo breaks opens down by client, and that breakdown is the real answer to how much preview room you've got. A trade list opening mostly on desktop Outlook can carry a longer, layered preview. A consumer list opening overwhelmingly on iPhone Mail can't.
Once you know the mix, test on the actual devices. Open a seed send on an iPhone where the sender is saved as a contact and again on one where it isn't, because that saved name genuinely moves the cut. Then do the same on an Android phone in the Gmail app.
This costs about ten minutes per campaign template, not per send. Most brands reuse two or three preview structures across the calendar, so get the structures right once and the work stays done. The habit shows up in the results we publish.
Set a length budget and build it into the template
Most of this piece is judgement. This part isn't. It's a checklist, and it belongs inside your campaign template, not in anybody's memory.
- The first 30 to 35 characters carry the complete idea, because on some client that's all anyone sees
- 60 to 70 characters is the safe zone for readers whose saved contact name eats into the preview space
- Anything past 90 characters is texture for desktop, never something the campaign leans on
- The preview never repeats the subject line word for word, it adds the missing detail
- If the preview field shows no live character count, count it yourself before you send
That budget is a target, not a matter of taste. Build it into the template once and the check takes seconds on every send after that. Easy!
Alex Gregoriades
Operations director at Engage Commerce, where he runs the accounts the writing comes out of.
FAQs
How long should email preview text be?
Long enough to use the room generous clients give you, but built so the first thirty-five characters carry the whole idea. Write the essential offer or deadline first, then extend the sentence for desktop readers. No single length is safe everywhere, which is why the budget matters more than the total.
Why does preview text look different on two identical iPhones?
Because the space depends on more than the device. A saved contact name takes room before the preview begins, orientation changes the line width, and larger text settings move the cut again. Two people on the same model can see different amounts of your sentence, so test with and without a saved contact.
What happens if I leave the preview text blank?
The email client fills the space with the first text it finds in the body, which is usually a view-in-browser link or the header navigation. That's worse than a truncated sentence, because it spends the most valuable line in the inbox on plumbing. Set it deliberately, every time.
Does preview text affect open rates?
It's one of three things a reader sees before opening, alongside the sender name and the subject line, so it carries real weight. Treat reported open rates with care though, because Apple's Mail Privacy Protection preloads images and inflates them. Judge preview changes on clicks from the send instead.
The cut isn't going to move for you
Apple won't widen the preview because your sentence deserved better, and no client publishes a promise about where the cut lands. The brands that win the inbox line write for the shortest window. Everything past it is a gift. Front-load the idea, test on the phones your list actually holds, and the preview starts earning its keep on every single send.
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