Free Email Subject Line Checker Length, Spam Words & Score
The subject line decides whether the email gets opened. Check yours for length (mobile cuts off around 40 characters), spam triggers, clickbait patterns, and personalization then get a score with specific fixes.
How this check works
- 01
Character and word counts are compared to the 20–40 character mobile sweet spot.
- 02
The line is scanned for spam triggers and clickbait markers ('Re:', 'Fwd:' fakes, urgency words).
- 03
Personalization tokens and lowercase, conversational style earn positive points.
How to fix common problems
Over 50 characters
It gets truncated on mobile, where most first opens happen. Front-load the important words.
Fake reply prefixes
'Re: your account' on a first touch is a known spam fingerprint and erodes trust if opened. Skip it.
Example
'Quick question about Acme's hiring' (34 chars, lowercase, specific) beats 'EXCITING OPPORTUNITY FOR YOUR BUSINESS!!!' on every metric this tool measures.
FAQ
- What is the best cold email subject line length?
- 20–40 characters or 3–6 words. Short enough to survive mobile truncation, specific enough to earn the open.
- Do emojis help or hurt?
- In cold B2B email, mostly hurt they pattern-match to promotional mail. Save them for warm lists.
- Should subject lines be capitalized?
- Sentence case or lowercase reads as personal; Title Case reads as marketing. For cold, lowercase often wins.
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