Tips for writing effective subject lines

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Email subject lines are the first thing that email recipients see in their inbox. It’s your introduction to the viewer, and it determines whether they will choose to engage with your brand or not.

Those 40 characters could get someone excited to read your email or annoy them enough to send it straight to the junk folder.

Subject Line Best Practices

Keep it clear and actionable: On average people get over 120 emails everyday. That's a lot of emails to sort through so it’s easy for an email to get overlooked.

People get annoyed at emails (and companies) that waste their time. Let your recipient know what your email offers and why they must open it. This is especially applicable if you have a special offer for them. Place the value upfront to entice the recipient. For example, “[eBook] 2020 Style Trends for the Chic Executive,” could be enough to get a busy corporate fashionista to open your email.

Don’t trick your recipients with a promising subject line and then underdeliver with the actual offer. For example, a subject line promising “50% off all items” creates certain expectations for your subscribers. Imagine if you only offer 50% off for a limited range of items — your subscribers aren’t going to trust you the next time you send a sales promotion.

Some examples of effective actionable email subject lines: 

  • You’re missing out on deals
  • Tonight only: A pizza lover's dream 
  • 25% off our favorite styles
  • Must-haves for your home office

Personalize: Make your subject line extremely relevant, timely, and tailor-made for the recipient to help you standout from all the other generic messages in their in-boxes. Utilize the information you know about your audience such as past purchases, birthdays, or locations to send a subject line that feels relevant. 

Some examples of personalized email subject lines:

  • Forget something? Here’s 25% off
  • Did you miss out on some of these new products?
  • April Birthday, here's 15% to celebrate 
  • Check out these hand-picked styles just for you

You can also use email personalization such as inserting your recipient's first name or adding emojis in your subject lines.

Align your messaging: In order to make sure your subject line aligns with the rest of your email message it’s helpful to write your subject line after you’ve developed your email copy. Don’t start with a movie title before putting together a script. Your email subject line acts as your title and will be the teaser that leads into the rest of your copy. Pull elements from your copy or headline into the subject line to give your key message more visibility.  

Keep it short: Space is limited in subject lines. If you want the entire subject to be viewable on mobile devices, the limit is 30-40 characters. Emojis have become more popular in recent years because they express a lot in one character, and they result in higher open rates. 56% of brands that use emojis in their subject lines have a higher unique open rate than competitors that don’t. Emojis help your email stand out in a crowded inbox, which is the first and most significant hurdle. However, it’s crucial to ensure that emojis fit the tone of your message and suit your brand before using them. For example, it would be off-putting if a funeral home used emojis, but it’s cute for emails about kids’ toys and dog treats.

Check out blog for more on emojis and the rules to use them. 🤓

What to Avoid

Spam: One of the most important considerations when putting together a subject line is making sure your email feels authentic and also gets past spam filters. Avoid terms that will make your email feel like click-bait or mislead the recipient of the email.

Some words to avoid:

Risk Free
You Won
Act Now
Order Now

Test your subject lines

Testing your subject lines with A/B or split test gives you confidence before sending your email to your entire audience. The most basic test metric for gauging results is open rates but you can also check unsubscribes rate or click through rates to determine how your email will perform.

If the contact is still not engaging with your emails, it’s time to consider cleaning them from your list. You want to know once and for all whether or not they should remain on your email list. If they continue to ignore you, it’s better to remove them, so they don’t pull down your engagement numbers. 


Every business is different so there’s no catch all solution for writing email subject lines.  The most important thing to do when putting together your campaigns is be creative and always test to figure out what works best in driving opens, clicks and conversions so you can reach your business goals.  

For more information on subject lines check out our blog. 

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