Shows your email subject line and preheader as a row in a phone inbox and in a desktop inbox, and checks their length against the figures Reavlo has verified. For anyone writing email who wants to see what the reader sees before the first line is cut.
How to use it
Write the subject line and the preheader. The preview updates as you type, and nothing leaves your browser.
- Write the subject line, or load the example to see how it reads.
- Write the preheader, the short line that follows the subject in the inbox.
- Compare the phone row and the desktop row to see how much of each line stays visible.
- Shorten the subject or move the key words to the front until it fits the recommended length.
How Reavlo tests this
The count is plain arithmetic, run in your browser. The figures come from Reavlo's platform limits data, and each shows the date it was checked against the documentation it comes from.
- Characters are counted as people see them: one visible character is one, so an emoji or a letter with an accent is a single character. This follows the Unicode extended grapheme cluster rules.
- The limit is the figure the sending tool documents. The recommended length is a suggestion, never enforced, and is marked separately from the limit.
- The phone and desktop rows differ only in width. The browser clips each line to the width of its row, with an ellipsis, as a stand-in for a real client.
- Where no figure is verified, nothing is claimed about a cut. A missing figure is deliberate, not an oversight.
Limits. The only email figures Reavlo has verified are Mailchimp's. Gmail, Outlook and Apple Mail publish no length for the subject or preheader, and each clips differently by device, width and font, so the rows are an approximation, not a measurement of any client. Send a test email to your own inboxes before a campaign.
Questions
How long should a subject line be?
Mailchimp recommends keeping a subject line short, and the tool marks that recommended length separately from the hard limit. Many phones show fewer characters than a desktop, so put the important words first.
Why are the limits Mailchimp's?
Reavlo lists a figure only when it is documented by the platform that sets it. Mailchimp documents its subject and preview text lengths; the large inbox providers do not, so no figure for them appears here.
What happens if I leave the preheader empty?
Most email clients then fill that line with the first words of the email body, often a "view in browser" link or a logo's text. Writing a preheader lets you choose what follows the subject.
Does an emoji count as one character?
Yes, here it does. A family emoji is built from several symbols joined together but shows as one character, and the tool counts it as one.
Can I share what I wrote?
Yes. The share link carries the subject and the preheader in the address after the # sign, which never reaches a server, and opening it recomputes the preview in your browser.