Email Subject Generator
Generate high-open-rate email subject lines for any topic.
Why email subject lines determine campaign success
The average professional receives 120+ emails per day. Your subject line has approximately 3 seconds to earn an open — or not. Open rates directly determine whether any of your email content is ever seen, making the subject line the highest-leverage element of any email campaign. Research by Copyblogger found that 8 out of 10 people will read a subject line but only 2 will click through to read the body.
Subject line formulas by objective
Character length guidelines
Email clients display different amounts of the subject line depending on screen size. Desktop clients show approximately 60 characters before truncating. Mobile devices show fewer — typically 40–50 characters. Put the most compelling information first so it is visible even when truncated. Aim for 41–50 characters as the optimal length for maximum visibility across devices.
Desktop preview: ~60 characters
Mobile preview: ~40 characters
Gmail on mobile: first ~30 characters + preheader text
Optimal strategy:
Put the hook in the first 30-40 characters
Use the remaining space to add specificity
Use preheader text (preview text) to extend the messageFrequently asked questions
What makes a subject line get opened?
Relevance, curiosity and brevity. Personalisation, a clear benefit, or a question often lift open rates, while clickbait that misleads hurts trust.
What is the ideal subject line length?
Around 30–50 characters so it is not cut off on mobile, where most emails are now opened.
Should I use emojis in subject lines?
Sparingly. A single relevant emoji can boost attention in a crowded inbox, but overuse looks spammy and can hurt deliverability.
How can I test subject lines?
A/B test two versions on a small portion of your list, then send the winner to the rest. Track open rates to learn what resonates with your audience.
25 proven subject line formulas combined with power words and triggers. Keep subjects under 50 characters. A/B test 2 versions for best results.