Email Subject Line Character Counter
Check your subject line length against desktop and mobile truncation limits. Most email clients cut off subject lines at 60 characters on desktop and 78 characters on mobile.
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Mobile truncation
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Subject Line Length Recommendations
Most email clients display between 60 and 78 characters of a subject line before truncating with an ellipsis. Key limits by client:
- Gmail (desktop) — 60 characters
- Gmail (mobile) — 78 characters
- Apple Mail (desktop) — 65 characters
- Apple Mail (mobile) — 78 characters
- Outlook (desktop) — 60 characters
- Yahoo Mail — 70 characters
For best results, keep your subject line under 60 characters to avoid truncation across all major clients. Front-load the most important information — put the key benefit or hook in the first 40-50 characters.
Why Subject Line Length Matters for Email Marketing
Subject line length directly affects open rates. Subject lines that are too long get truncated in the inbox, hiding your key message. Subject lines that are too short may not provide enough information to convince a subscriber to open.
The ideal email subject line length is 40-60 characters. Research shows that subject lines in this range consistently achieve the highest open rates across industries. This is short enough to avoid truncation on most clients while long enough to communicate a clear benefit or hook.
Mobile is particularly important — with over 50% of email opens happening on phones, the mobile truncation limit of 78 characters is the most critical threshold. However, even on mobile, the key information should appear in the first 40-50 characters since the preheader text also competes for space.
Subject Line Length by Industry
Optimal subject line length varies by industry. Promotional emails benefit from shorter subject lines (30-50 characters), while newsletter and educational content can use longer subject lines (50-70 characters). The best approach is to A/B test subject line length on your own audience.
Use this character counter alongside our Subject Line Analyzer to score your subject lines for sentiment, spam triggers, and mobile rendering. For wider campaign analysis, see our Campaign Performance Calculator.