I recently received an email from a retailer that I have previously purchased a product from. Their email subject line was a play on the classic wedding phrase, “Something old, something new, something borrowed, something blue.”
Instead of helping me find the perfect wedding dress, they wanted me to buy the same product that I had previously purchased from them. The email didn’t make sense for my situation, and their email subject line was a bit of a stretch.
This is a classic example of a subject line that gets your email deleted immediately. It’s not relevant to the recipient and is a bit of a stretch.
When it comes to email marketing, the best subject lines tell what’s inside, and the worst subject lines sell what’s inside.
So, what works? Here are 13 email subject line formulas, each with an example. Try implementing one of these subject line formulas, and track your email open rates to see which one your audience likes.
1. Get straight to the point
Inboxes are crowded places. People are busy and don’t have time to figure out what your email is about. That’s why it’s so important to get to the point.
If you can, keep your subject line to 50 characters or fewer. That way, it’s less likely to get cut off in your recipient’s inbox view.
In this example, the company is sending a quick reminder about a webinar. The subject line is short and to the point. There’s no confusion about what the email is promoting.
2. Create urgency
If you want to drive action, creating a sense of urgency is a proven way to get it done. Your subject line is the first place to start.
You can create urgency in a few different ways. You can announce a sale or promotion that has a deadline. You can also let your readers know that they’re about to miss out on something if they don’t act fast.
In the example below, you can see how the subject line creates urgency by letting the reader know that they have a limited time to get 50% off of their next order.
This is a great way to get your subscribers to open your email and take the action you want them to take.
3. Ask a question
Subject line: Want to grow your business?
Asking a question in your email subject line is an effective way to grab someone’s attention. Questions are a great way to encourage a back-and-forth between you and your email recipients. Plus, a question sets the expectation that your email will provide an answer.
Asking a question in your subject line can also make your email feel more personable and conversational. This can help you build trust with your audience.
4. Make a startling statement
Don’t be afraid to shock your readers. It might be just what you need to get them to open your email.
If you have a big announcement to make, the email subject line is a great place to get it done. That’s what we did in the email below.
We let our readers know about a new feature with the subject line “New: Get more done with our new feature.”
5. Speak directly to the reader
We all love to hear our own names, and the same goes for seeing personal pronouns in the subject lines of emails.
Using “you” and “your” in your subject lines can help your readers feel more connected to your brand and your message.
6. Use the word “you”
There’s no better way to make someone feel like you’re talking directly to them than to use the word “you” in your email subject line.
In the example above, the subject line “You’ve been selected” makes it sound like the recipient has won something or gotten a special offer.
It’s a classic example of how using the word “you” in your subject line can make your email feel more personal and engaging.
7. Offer a how-to guide
If you have a valuable piece of content, like a guide or a whitepaper, and you’re trying to get your contacts to download it, you can use email to promote it.
In your email, you can use the subject line to tell your contacts what they’re going to learn in the guide. This will help them see the value of the content and encourage them to open the email to learn more.
For example, if you’re promoting a social media guide, your subject line could be “How to Create a Social Media Strategy in 6 Easy Steps.”
8. Make an announcement
Sometimes the best way to get someone’s attention is to just come out and say it. If you have something important to share with your audience, don’t be afraid to make an announcement in your email subject line.
As long as you’re not overselling, you can use this tactic to build suspense around a new product launch, a big promotion, or even a new piece of content you’ve created.
Pro Tip: If you’re going to use an announcement in your subject line, make sure it’s something that’s actually worth getting excited about. Otherwise, you risk losing the trust of your audience and hurting your open rates in the future.
9. Test your subject lines
A/B testing your email subject lines is the best way to find out what works for your audience.
To do this, create two identical emails with different subject lines. Send the emails to an equal number of random recipients, and then measure the open rates.
After you’ve collected your data, use it to inform your future subject lines. Over time, you’ll get a better understanding of what your audience likes and doesn’t like.
10. Use numbers
If you’ve ever written a blog post, you’ve probably used a number in your title. That’s because it’s a great way to set clear expectations and let the reader know exactly what they’re going to get.
The same goes for your email subject lines. If you’re sharing a list of tips, tools, strategies, or anything else, make sure you let your subscribers know that by using a number in your subject line.
11. Personalize your subject line
Personalizing your subject line is a great way to make your email content feel more relevant and valuable to your audience.
Personalization can be as simple as adding your recipient’s name to the subject line. Most email marketing tools have a personalization feature that allows you to insert a contact’s name into your subject line. You can also personalize your subject line by segmenting your email list and sending targeted emails to specific groups.
For example, you could send a targeted email to subscribers who have recently purchased a product from your online store. You could personalize your subject line by including the name of the product they purchased.
Personalizing your subject line is a great way to make your email content feel more relevant and valuable to your audience.
12. Keep it short
If you’re not sure what to write in your email subject line, just keep it short and sweet. It’s a simple way to make sure you don’t lose your reader’s attention before they even get to your email.
And if you’re not sure how to keep it short, we have a few examples for you to choose from.
13. Highlight referrals or rewards
Referral and reward-based emails consistently perform well because they offer clear, tangible value. When recipients see that there’s something in it for them—or their friends—they’re much more likely to open the email.
Subject lines that reference referrals, rewards, or invitations tap into curiosity and reciprocity. For example:
- “Give $20, get $20 — invite a friend”
- “Your referral reward is waiting”
- “Know someone who’d love this? Get rewarded”
If you run a referral program using tools like ReferralCandy, you can easily trigger these types of emails automatically when customers become eligible for rewards or when a referral is successful. Because these emails are tied to real user actions and incentives, they often feel more relevant and timely than generic promotional emails.
Using referral-focused subject lines is a smart way to boost open rates while encouraging word-of-mouth growth at the same time.
Conclusion
Your email subject line is the first thing your subscribers see in their inbox. So, it’s important to get it right, and it’s worth taking the time to think about how to write good email subject lines.
If you’re interested in learning more about email marketing, check out our guide to creating email marketing campaigns people actually click on.
