What is a good email subject line length?

The ideal email subject line is 40-60 characters (6-10 words). This range ensures your full subject line is visible on both desktop and mobile inboxes. Subject lines under 40 characters can feel vague, while those over 80 characters get truncated on most devices.

How do I improve my email open rates?

Focus on three things: write subject lines that create curiosity or promise clear value, personalize with the recipient's name or behavior, and A/B test every send. Also clean your list regularly — removing inactive subscribers improves deliverability and open rates.

What are preview texts and why do they matter?

Preview text (or preheader text) is the snippet shown after the subject line in most email clients. It acts as a second headline and can increase open rates by 10-20% when used strategically. Always write custom preview text rather than letting it default to your email's first line.

Does this tool use AI or an API?

No. This tool uses curated, template-based generation — no API calls, no AI models. It replaces placeholders with your topic to produce instant results. This means it's fast, free, and works offline.

Can I use emojis in email subject lines?

Yes, but use them sparingly. One well-placed emoji can increase open rates by 5-10%, but multiple emojis can trigger spam filters. Test emoji vs. no-emoji variants with your specific audience before committing.

Is the Email Subject Line Generator free?

Yes, the Email Subject Line Generator is 100% free with no signup required. Generate unlimited subject lines for any email campaign, any time.

Subject Line Engine

Email Subject Line Generator

Generate high-open-rate subject lines for any email campaign. Template-based, instant, and completely free.

Pro Tip: Subject lines between 40-60 characters have the highest open rates. Aim for 6-10 words.

Your subject lines will appear here

Enter your product or topic and select an email type to start generating.

Email subject line best practices

Keep it short (40-60 chars): Subject lines with 6-10 words get the highest open rates. Mobile inboxes truncate after ~35 characters, so front-load the value. Use our headline analyzer to score your subject lines before sending.

Use personalization: Emails with personalized subject lines are 26% more likely to be opened. Include the recipient's name, company, or a recent action. Combine this with AI content generation for email body copy.

Create urgency (carefully): Words like "last chance" and "expires tonight" boost opens, but overuse trains subscribers to ignore you. Save urgency for real deadlines.

A/B test relentlessly: Even a 1% open rate improvement on a 50,000-subscriber list means 500 more readers per send. Test one variable at a time: length, emoji, question vs. statement. Run tests with our A/B test generator, then schedule your campaigns with PostEverywhere's scheduler.

Open rate benchmarks by industry

Average email open rates vary by industry. Use these benchmarks to measure how your subject lines perform relative to your peers.

E-commerce15-20% open rate
SaaS / Tech20-25% open rate
Media / Publishing22-27% open rate
Non-profit25-30% open rate
Education23-28% open rate

Source: Industry averages across major ESPs, 2025-2026 benchmarks. Your mileage may vary based on list quality and send frequency.

A/B testing your subject lines

Test one thing at a time

Change only the subject line between variants. Keep the sender name, send time, and preview text identical so you know exactly what moved the needle.

Use a meaningful sample size

Send each variant to at least 1,000 subscribers before declaring a winner. Small samples produce unreliable results that won't hold up at scale.

Wait 2-4 hours before judging

Open rates spike in the first hour but continue climbing for several hours. Give your test enough time to capture late openers before picking a winner.

Need to write and schedule content across all your channels? Try PostEverywhere's social media scheduler to manage email-to-social workflows in one dashboard.

How to Use the Email Subject Line Generator

Enter your product or topic

Type in what your email is about (e.g., SaaS Onboarding, Running Shoes, AI Tools) so subject lines are tailored to your audience.

Select your email type

Choose from 6 campaign types: Newsletter, Promotional, Welcome, Re-engagement, Event, or Cart Abandonment.

Copy and test

Browse 6 generated subject lines with character counts and preview text. Copy your favorites and A/B test them in your next send.