Email preview tool

Before anyone opens your email they see three things: your name, your subject line and one line of preview text. How much of each fits depends on the screen. With the example email on this page (a 40-character subject line), here’s how much of the preview text shows:

How we measure: each screen is drawn at its real size (an iPhone screen is 390 by 844 points; Gmail on a laptop is a 1280-pixel-wide window) in the fonts those apps use, and the tool counts how many characters fit before the app cuts them off. Your phone model and text size setting can move it by a few characters. Measured 16 October 2026.

Your numbers change with your words, because a W takes more room than an i. The tool measures yours as you type, and the preview text checker shows the cut on every screen. For subject lines, see how long a subject line should be.

Gmail’s own way is to send a test to yourself and check it on your phone and your laptop. This tool shows the same screens without sending anything: the lock screen notification, the Gmail app inbox, the opened email and Gmail on a laptop, as the person you’re writing to will see them.

On a phone, the lock screen notification shows your name, your subject line and the first line or two of the email. In the Gmail inbox they see your name, your subject line and one line of preview text, among the other emails they got that day. That’s all they have to decide whether to open it, and it’s what this tool shows.

In a plain-text email, like most sales and cold emails, Gmail uses the first words of the email as the preview text. Your opening sentence is your preview text, so it has to earn the open.

A designed email, like a newsletter, can set its own preview text (often called a preheader). Use “Add preview text” in the tool to see how it shows.

• It shows the lock screen notification on an iPhone or an Android phone, the Gmail app inbox with your email among the other emails they get, the email opened, and Gmail on a laptop, in light and dark, with a full screen try-out you can tap through.
• It compares up to four versions side by side.
• It doesn’t show how a designed (HTML) email looks once it’s opened in each email app. For that you need real screenshots from a paid service such as Litmus or Email on Acid.
• It doesn’t check whether your email lands in spam.

It depends on what you want to check. To see what people see before they open it (the lock screen, the inbox line, how much of your words fit): this tool, free, with no sign-up. To see how a designed HTML email looks opened in Outlook, Apple Mail and the rest: Litmus and Email on Acid take real screenshots and are paid; Unspam lets you try it without signing up. Litmus’s old free sender, PutsMail, has been retired.