How to write great subject lines

Even though you're only sending emails to people who've consented to receive them, you still have to compete for your contact's time and attention to get your email actually read. Here are tips to help you write a subject line that grabs your audience and has a greater likelihood of being opened.

1. Relate it to the community. If you have an established readership, referring to the newsletter by name helps recognition — but add a twist so recipients know it's fresh. My own newsletter always ends with its name, but I attach a short phrase at the start referring to the content. Our tests show that adding the extra catch‑phrase alongside the standard name achieves a higher open rate. Nothing is more unenticing than every email being the same three words, like “Acme Sports Newsletter”.
2. Inspire thought. A catchy phrase that makes people think is an excellent way to elicit an open — but pick your audience and don't overdo it. A serious topic calls for a more sophisticated, thought‑provoking line.
3. Relate it to current news. Mentioning a current news topic related to your email increases opens, because your audience wants to stay abreast of the hot topic. Just make sure your content really does add that value.
4. Focus on a benefit. Consider your audience — what benefits one may not benefit another, so when you articulate a benefit, target your list more precisely. Steer clear of overused words that make you look like a fly‑by‑nighter or spammer (“free”, “cheap”), and don't make offers that sound too good to be true. Phrase the subject in the common vernacular of your list (and don't use the word “vernacular”!). The benefit may not be an offer at all — it might be other important information.
5. Use AI. Stuck for a headline? Use the eNudge AI Subject Line Generator to write five options on a topic and pick the best — or ask it to refine the tone or style and go again. Read more about the AI subject line generator.
6. Mind the length. Some experts recommend no more than seven words — short and sweet to grab attention without wasting time. Others have reversed the trend with very long subjects. Consider your audience, and perhaps mix it up — but the more concise your headline, the more likely all of your audience will take it in.
7. Use examples from the media — high‑quality news outlets, or emails that grabbed your own attention. When a headline captures you, analyse why you gave it your time, then apply that to your organisation.
8. Be distinct from spam. Take a peek at the emails in your junk folder, and make sure your subject lines look nothing like them.
9. Follow the trend — or not. Trends in how headlines are written come and go. Early in a trend, using that phrasing can help opens; once it's hackneyed it can have the opposite effect. At the time of writing, “xyz thing… here's what you need to know” has become over‑used, and I inwardly roll my eyes every time I read it.
10. Go easy on capitals and exclamation marks. All caps, lots of exclamation marks, or other special characters should be used with caution — they can make your email look like spam, or like an offer that's too good to be true.
11. Test. The best way to gauge the right subject line for your audience is to test. If your list is large enough, send several messages testing different subject lines, then send the highest‑opening one to the remainder of your list. This is known as A/B testing.

Of course, the subject line isn't the only thing that determines whether your email gets read. You might also like “The anatomy of a great email campaign”.

Happy eNudging!

Heather Maloney
Originally authored May 2007; updated June 2025.