Master the art of email subject lines: 5 proven tips and 3 examples

Email marketing can be a highly effective way to reach customers, whether your business is B2B or B2C. But in order for it to work, you first need your audience to actually open your emails – this is where your subject line comes in.  

Here are five tips for crafting effective email marketing subject lines along with real-life examples from leading brands of what this looks like in practice. 

1. Make a good first impression 

Nearly half of email recipients say they open an email based on the subject line alone, according to research from lead generation software company OptinMonster. 

A subject line is your first impression to email recipients. If it’s compelling, it will draw them inside. If not, they won’t get past the front door. 

Recipients will be more likely to open your email if the subject line catches their attention and resonates with them. Include a value proposition in your subject line (i.e., What’s in it for them? Why should they care?). Relevance is key, so tailor your message to your audience and personalize your emails when possible.  

2. Keep it brief 

As a general rule of thumb, be concise with your subject lines. MailChimp recommends limiting subject lines to nine words or 60 characters. However, some other email providers and industry experts suggest sticking to 50 characters or less.  

3. Avoid spam filters 

OptinMonster also found that 69% of recipients will mark an email as spam based on the subject line alone. Avoid spam filters by following email marketing best practices and by avoiding potential trigger words such as “free,” “act now,” “risk-free,” “guaranteed, and “winner.” 

4. Set clear expectations 

A strong email subject line should also clearly set expectations and let the recipient know what they can expect to find inside. In other words, the email content should match the subject line, not feel disconnected – or worse, feel like a bait-and-switch. 

5. Use the preheader wisely 

Finally, don’t forget about the email preheader, which is the brief snippet of text that appears after the subject line in an inbox. A compelling preheader complements the subject line and entices engagement. 

Email marketing examples from top brands 

Here are a few examples from companies using email subject lines effectively. 

Example: Panera Bread 

• Subject: Enjoy a cup of soup for just $1. Don’t miss it! 

• Preheader: When you buy a whole sandwich or salad.  

• Why it works: The subject line is brief and the value proposition is specific, enticing, and action-oriented. The pre-header adds helpful context and clarity.  

Example: Avis  

• Subject: The Avis Fall SUV Sale is Back for a Limited Time! 

• Preheader: SUVs starting as low as $55/weekend day. 

• Why it works: The subject line conveys a sense of urgency, and the preheader provides more specificity about the offer. 

Example: Southwest Airlines 

• Subject: Lisa—now, for a limited time, earn tier status even faster.  

• Preheader: There are now even more ways to earn. 

• Why it works: The subject line is personalized and time-based with a clear value proposition. The preheader provides additional explanation. 

Writing effective email subject lines and pre-headers, such as in the examples above, helps to increase open rates, which in turn can lead to higher click-through rates (the percentage of people who click a link in your email to go to your website) and ultimately conversions. Before sending your next marketing email, review the tips above to improve your odds of a successful send.