Outlook subject (web)
Outlook · WebYour brandLast chance: 30% off everything ends tonight at…midnight9:41
Outlook · Web · Subject line
Outlook subject (web) length checker (~51 characters)
About 51 characters at a 1400px-wide window. Modeled as a pixel box calibrated to the character count seen on the device, so wide and narrow letters are handled.
Last reviewed · How we measure
Gets cut
The Outlook subject (web) limit at a glance
- Limit
- about 51 characters (351px)
- How it’s counted
- By rendered width in the system font at 14px, so wide letters use more room.
- When it’s too long
- Cut on screen with “…”
- Where the number comes from
- Measured on devices
- Last reviewed
How to write for it
- B2B audiences read in Outlook, so check this one for work emails.
Where you’ll see the Outlook subject (web)
Outlook on the web shows the subject on its own line in the message list, and the reading pane makes that list narrow.
Before and after
Action required: please review and approve the updated vendor contract before Friday
Please approve the vendor contract by Friday
Common mistakes
- Starting with “Action required” or “FYI”, which use up the width without saying what’s needed.
FAQ
Outlook subject (web): questions
What is the Outlook subject (web) limit?
About 51 characters (351px). About 51 characters at a 1400px-wide window. Modeled as a pixel box calibrated to the character count seen on the device, so wide and narrow letters are handled.
Does Outlook show fewer characters than Gmail?
On the web, yes: about 51 characters fit at a 1,400-pixel-wide window, against about 88 in Gmail, because the reading pane takes much of the screen.
What happens if my subject line is too long?
Outlook · Web still shows it, but cuts it with “…”, and anything past the cut is invisible to most people.
Why does the character count change?
This screen cuts by width, not characters. Wide letters like W and M use up to four times the room of i or l, so two texts of the same length can be cut in different places.