How to use the length and preview checker
Enter a topic, pick a mode and generate a set of lines. Each row shows the full subject, its character count, a phone-style preview of about the first 38 characters, and notes such as “may truncate on many phones” or “all caps”. Send a draft to a temp mail inbox if you want to see how a real client displays it. If a verification email never arrives, read verification code not received.
Worked examples
These static samples show the sort of line the generator writes. Character counts include spaces:
| Mode | Subject line | Chars |
|---|---|---|
| Marketing | A closer look at winter jackets | 32 |
| Job | Application for the product designer role | 42 |
| Follow-up | Following up on the proposal | 28 |
| Black Friday | Black Friday notes on winter jackets | 36 |
Subject lines are not the same as deliverability
A clear subject will not help if the message fails authentication or lands in spam. To inspect a received message, paste its headers into the email header analyzer. To see who hosts an address, use the email host lookup or the MX lookup. If you are checking the address itself, start with the email address validator.
Questions
How long should a subject line be?
There is no official limit that every inbox shares. Many phone previews show about the first 35 to 40 characters; desktop previews show more. This tool flags lines over 60 characters because they are the ones most likely to be cut off. Treat that as drafting help, not a rule.
Will a shorter subject get more opens?
Nobody can honestly promise that. Open rates depend on who you write to, whether they know you, and whether the message lands in the inbox at all. The generator only writes options and measures length.
Are the subject lines uploaded?
No. They are built in your browser from the topic, company and name you type.
What do the four modes change?
Marketing writes curiosity and update lines. Job writes application and interview follow-up lines. Follow-up is the shorter check-in style. Black Friday is seasonal shopping language without invented discounts.