Countless articles have been written about what makes a great subject line. The type of subject line that inspires consumers to open your emails and actually read them. But out of the seemingly never-ending list of factors to consider, what really works? Well, you’re in luck! We’ve done the research for you and have compiled the ultimate list of tips, tricks, best practices, and suggestions to help you perfect your next subject line!

But first, a small disclaimer. Subject lines are only as effective as the list they’re targeting. You won’t increase open rates if the emails are targeted at the wrong audience. You should know the demographic and psychographic of your consumers like the back of your hand. So follow these recommendations all you like, but make sure your emails are being sent to the right people. Otherwise, you won’t see results. 

How to Write Great Subject Lines


  • Keep your subject lines simple and specific.
  • 40 to 50 characters are ideal. Consider how the subject line will be displayed on a desktop, versus tablet versus mobile. These all have different screen sizes. Send test emails to yourself and check on all devices for which works best.
  • Front-load your subject line, so the content is upfront and will not get cut off by different sized devices.

Tone of Voice:

  • Match your email tone of voice to your website tone of voice. Not sure what that is? When in doubt, use a friendly and conversational tone of voice.
  • Make sure the subject line has the same tone of voice as the content of the email. If it is a serious email, the subject line shouldn’t be quippy.
  • Use references that your audience will understand.

Capitalize on Human Tendencies:

  • Capitalize on FOMO – Fear of Missing Out. People have a fear of missing out on saving time or saving money, or missing out on attending an event that other people will be at.
  • People hate being wrong – can you craft a subject line around this? Perhaps you can inspire consideration by indicating that something your consumer is doing might be incorrect?


  • Localize, personalize, and target – can you incorporate the recipient’s name into the subject line? What about their location or gender? Can you dig deep into their actions on your website? Personalization is key.
  • Relate to the time of year/time of day that your email is being deployed. Example: Winter or during the afternoon workday slump – 2:00pm-ish.

Things to Consider:

  • The preview text of the email body is important. Make sure your subject line and preview text are consistent or even play off each other.
  • Make sure the preview text isn’t the notification to view the email in a web browser or unsubscribe information. That information should be moved to the bottom of the email.
  • These common buzzwords that always seem to perform well with open rates: Last Chance! Free Shipping! Email Only Offer! Ends Today! Sale! Free Delivery! Discount! XX% Off!
  • Other techniques that work well to increase open rates are asking a question, using stats, or numbers if possible. Puns help too.
  • Don’t use all capital letters, this alerts spam filters.
  • Avoid unnecessary punctuation, symbols, and brackets. These can also land your email in the spam folder.

Let’s review some examples. First off, I only check personal emails on my mobile phone — rarely do I sign in through my desktop. So subject line length matters a great deal to me, along with preview text.

Second, I love Urban Barn. Check out this email I received. I love the subject line! Not only did “Go Mad” catch my attention, but win $1,000 definitely did. It also fits, so I can read the whole thing on my device without any text being cut off. My only issue is that the unsubscribe information and company address is the preview text.


Then, a few days later I received the following email from Urban Barn. Apparently, there was some controversy over their “Go Mad” email content, in that the copy, “Have a drink. Heck, have a smoke” didn’t go over well. (See original “Offensive” email above).

While I was not in the slightest bit offended by the original email, the subject line addresses the content of the apology email and matches the tone of the email. Serious email, so a serious subject line, that is straight to the point.


What about this email from ASOS? The subject line and preview text play off of each other. The subject line is personalized by the use of “your” and applies to the time of year.


Here is an excellent example from Sole Society about personalization. I left some items in my online shopping cart and then left their website. They reminded me of my un-purchased items! This subject line reflects my online activities on their website and is highly personalized to me. The body of the email even says my name. However, the only downfall is that the preview text is about viewing the email in a web browser.


The best advice we can offer? Test and analyze. Try A-B testing different subject lines and monitor the open rates. Also, keep an eye on the emails you’re receiving. What about the subject line compelled you to open the email? You can learn from your own experiences!

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