Email Subject Line Checker
Check an email subject line for length, ALL CAPS words, extra punctuation, emoji and words commonly linked with spam, with suggestions to review.
Check an email subject line for length, ALL CAPS words, extra punctuation, emoji and words commonly linked with spam, with suggestions to review.
The subject line decides whether an email gets opened. Most inboxes show only the first 40 to 60 characters, and some wording can make a message look like spam.
Type your subject line to see its length and a list of things worth reviewing: all-caps words, repeated punctuation, emoji and common spam trigger phrases.
The checker applies simple rules to your text. It counts characters and warns above 60 or below 20, counts words written in all capitals with four or more letters, counts exclamation marks and emoji, matches the text against a built-in list of about thirty phrases common in spam, and flags a leading RE:, FW: or Fwd: and repeated symbols like $$ or !!!. Matching is by whole word, so the word free is caught but freedom is not. The list is short and English only, and it simply highlights patterns.
Inbox providers decide placement using sender reputation, authentication (SPF, DKIM and DMARC), engagement history, complaint rates and message content, so a clean subject line cannot rescue a poor sender, and a flagged word does not by itself send mail to spam. Display length varies too, since mobile apps show roughly 30 to 40 characters while desktop clients often show more, and the preheader text fills the rest of the preview. The most reliable way to learn what works for your audience is an A/B test of subject lines on a small portion of the list.
No. Spam filters weigh the sender reputation, authentication, content and more. This is a quick check of common subject line problems.
Around 30 to 50 characters usually shows in full on mobile and desktop.
Not necessarily. A word like free is fine in context, but combined with caps and punctuation it looks suspicious.
No. It is checked in your browser.
No. Delivery depends mainly on sender reputation, authentication and recipient engagement. This tool only highlights common subject line patterns, so a clean result does not guarantee that the email reaches the inbox.
Not necessarily. One or two can help a message stand out, but many look spammy and may render differently across clients. The tool flags more than two, so test with your own audience.