Subject line & preheader tester
Your subject is cut at about 40 characters on mobile, 55–60 in Outlook and 70 in Gmail desktop — so the same line lands differently in every inbox. Type below to see the exact truncation per client, computed by the Emailens engine.
Frequently asked questions
How long should an email subject line be?
Aim for roughly 40 characters so it survives the tightest common view — Gmail and Apple Mail on mobile show about 40. Gmail desktop shows around 70 and Outlook 55–60, so front-load the words that matter in the first 40.
What is preheader (preview) text?
The preheader is the snippet shown after the subject in the inbox list. Gmail shows up to ~90 characters of it, Outlook on the desktop only about 35. If you leave it empty, clients pull the first text in the email — often 'View in browser' or an address block.
Do emojis in subject lines help or hurt?
One emoji can lift attention, but some clients and corporate Outlook installs strip them or render an empty box. Keep to zero or one, and make sure the subject still reads correctly without it.