Email Subject Line Best Practices for 2026

In 2026, it might seem like all the odds are against you when it comes to email marketing. From enduring Apple Intelligence’s mail summary changing your perfectly crafted preview text to adhering to stricter SPF and DKIM authentication requirements, it might feel like there’s nothing in your control. But there is! And it’s your email subject line.

How to write the best subject lines

That’s great news, because subject lines are essential to improving your open rate and managing your brand identity. There are few ways to “get it wrong,” but there are plenty of ways to do better. Follow these email marketing best practices, and not only do you get a sense of control in an otherwise chaotic marketing world, but you also​ optimize your copy and improve your metrics.

1. Include CTAs whenever possible

If you’re anything like me, when you receive an email, you want to know immediately why the f*** someone emailed you. That’s why a well-crafted CTA can significantly increase the chances of your email being opened by the recipient. 

Examples: 

• Take 20% Off Your Next Purchase 
• Action Required: Confirm Appt. By [deadline]
• Schedule a Free Beauty Consultation

2. Curate urgency and exclusivity

Everyone gets FOMO from time to time, so creating a sense of urgency and exclusivity is a good way to capture attention and entice action. The key is to avoid overusing this device to prevent looking like spam.

Examples: 

• Sale Ends Tonight: 50% Off Bestsellers
• Only 3 Spots Left for Friday’s Event
• Limited Edition [Product] Drops Today

3. Add numbers when necessary

According to Mailchimp, emails with numbers in the subject line have a 29% higher open rate and a 20% higher click-through rate compared to those without numbers. Numbers imply proof. People believe numbers. (Just don’t game the system with “Discount 4 You.”)

Examples: 

• 24 Hours Left to Claim Discount
• 12 Ways to Save Big on Shipping
• VIP Offer: 15% Off Your Cart

4. Prioritize the first 30-40 characters

While total subject lines can be 50-40 characters in length, it’s important to prioritize the first 30-40 characters for users on mobile devices. Plus, there may be laptop or tablet users who keep their email browsers small and will only see the first 30-ish characters.

Examples: 

• BOGO Offer | Summer Sale
• Free Shipping for ALL Orders
• Your Trial Ends Sunday

5. Ask an engaging question

What sets interrogative sentences (aka questions) apart from declarative, imperative and exclamatory ones is that they are interactive by nature. Attract attention and encourage user engagement by asking a relevant and thoughtful question. 

Examples: 

• Ready to Book Your Next Class?
• Did You Forget Something In Your Cart?
• Hey, Care for a Freebie?

Are there caveats to best practices

With every set of “rules,” there are always exceptions. Let the best practices guide you rather than rule you. You should never stop testing your subject lines, whether that’s to create or confirm your hypotheses.

Use the system to conduct A/B tests

You can follow all the best practices out there, but the only true way to know what works best for your audience is to perform high-velocity A/B testing. A best practice isn’t a golden rule; it’s simply the most commonly effective option. But what works for everyone else won’t necessarily work for you. 

Here are some tests to try out:

• Numeral vs. spelled-out number vs. no number
• Long text vs. short text
• Emoji vs. no emoji
• Straightforward vs. flowery
• Title case vs. sentence case vs. lowercase
• Serious vs. silly
• Personalized vs. broad

Always avoid doing these things

Almost everything is worth a test. Almost everything. If you’re reading this blog post, chances are you’re probably already using a lot of the best practices we shared. So, here are a few things to avoid to prevent hurting your email marketing performance:

• Don’t use strange or excessive punctuation. (ex. !!)
• Don’t use ALL CAPS. No one wants to be screamed at.
• Don’t use emojis unnecessarily or in lieu of words. Use supplementally instead.
• Don’t write “you”/”your” when dynamic data (ex. *|FNAME|*) would be more personal.

Where can I find the email experts

Email marketing rules are always changing. As an entrepreneur or business leader, the last thing you want to do is waste your time keeping up to date on every little email tip. Partner with our award-winning agency and let our experts take care of your email needs.