Cold Email Subject Line Analyzer
Enter your subject line below. We'll score it for length, personalization, and spam risk.
Character Count
0
Type a subject line
Word Count
0
Aim for 3–6 words
Spam Risk
Low
No spam triggers
Suggestions
Want AI-generated subject lines?
Sales.co generates personalized subject lines using AI, tested across millions of cold emails for maximum open rates.
Generate with Sales.co →Cold Email Subject Line Best Practices
The optimal cold email subject line is 3–6 words and under 50 characters. Data from 2M+ cold emails shows that shorter subject lines get 21% higher open rates than longer ones. Subject lines with the recipient's first name or company name get 26% higher open rates.
Avoid all caps, excessive punctuation (especially multiple exclamation marks), and promotional language. The best cold email subject lines read like a message from a colleague, not a marketing email.