What email subjects should I use?


Subject of email could be one of the factors that attracts attention your audience, it provides a brief information about the content of the email, so that the recipient can quickly decide whether the email is relevant and important for them or not? Usually an interesting subject can also help differentiate your email from other emails competing in the recipient's inbox, therefore the subject of the email is important for the success of your marketing strategy.

Remember the preview text

The preview text is as important as the subject, so never think of the subject in isolation, there is always its accompanying element, which is the preview text. If I had to rank the importance, it would be 50-50. So when you are thinking of the subject, think of the preview text at the same time.

No need to sell in the subject

Remember that the main purpose of the subject and preview text is to get the recipient to open the email. You don't need to tell the whole story or start selling there. All you need is to arouse enough curiosity for people to open the email, and of course you have to have a great opener in the email itself.

Curiosity plus benefit

The most successful email subjects combine the element of curiosity and the element of benefit, which means you need to give a hint of the benefit that you will talk about in the email and a little arouse the reader's curiosity. Do you want some examples? Let's take an example from chocolate sales, you can use the subject "The secret of chocolate that you never knew" or "This is why you should try premium chocolate from this brand" because it is sensitive, so you have to be careful not to disappoint your audience.

Subject length

I am sometimes asked about the optimal number of characters for an email subject. Honestly, if you are too focused on counting characters, you are doing something wrong. In general, the shorter, the better, but the most important thing is that the subject and preview text fit in the inbox preview on desktop and mobile. Send yourself a test and review it on your phone, make sure that you can read the entire subject and enough preview text so that the message you want to convey is visible.


There is a lot of advice out there about including numbers in email subjects. We used to follow this advice, and it did work two or three years ago. However, in all our latest A/B tests, subjects with numbers lost to subjects that were more creative and driven by curiosity without numbers, even when talking about discounts or 30% offers. So, curiosity is more important than numbers in email subjects.


Emoticons in the subject are a good idea if they suit your audience, with the caveat that you don't overdo it. Use emoticons wisely, and you will see good engagement.

Avoid spam triggers

There are certain words that are more likely to trigger spam filters than others, and it's not just words, but punctuation marks too. For example, using capital letters and excessive exclamation marks significantly increases the likelihood of your email ending up in the spam box. 

Spam trigger words include words like discount, free, sign up now, and so on. However, using one of them is not a direct sentence to email punishment, you can use them in contexts where they are appropriate. Make sure your sender reputation is clean and you are not sending to a purchased list.


Using clickbait in the subject is a bad taste for email marketers, but I would be lying if I said I was never tempted. Click bait is anything that can almost guarantee you a click because you play on the basic human emotions.

Some examples of clickbait like "Congratulations" made me click because I thought I had won something, but it turned out to be just a Cyber Monday email and the content of the email was not related to the subject.

Whereas they could have tried to tell me that because I was a previous subscriber or a member of their club (which I did), I heard about the discount first or I got a bigger discount but they didn't. So when the second email came two days later, pretending to be a transactional email about an unread message, I was already suspicious of suspicious things, and it turned out to be just another sales email, again with no connection to the subject.

When you do things like that, of course you make people open, but you lose their trust. In my opinion, that is a big price to pay for one opening.

Using prefixes like "Forward" or "Reply" is good for getting someone to open, but unless it's really relevant to your message and you can make a connection with it in the content of your email, I suggest not doing it. Email marketing is a marathon, not a sprint, and your customer's trust is the most valuable asset you have, use it wisely.


Of course, the more personal your subject, the more effective they will respond to things they recognize, which is true, but you don't always have the data to personalize all your emails.

an example of when you can do it in your abandoned cart series, if they have started checkout, they have given you their first name and you know the name of the item in their cart, so you can personalize it with either one.

In your post-purchase series you also have their name and the product they have purchased. After a customer review, if your review platform is integrated with your email platform and you collect additional data in your review form, then you can personalize your email with that data.

To have more of your customer data at hand, use multi-step forms to collect that data at the time of registration. For example, after you ask someone for their email address, you can also ask for their gender if relevant to your product, and then what product category they like, then when you send a welcome email or email campaign, personalize your email based on that data.

Use lowercase letters

I saved this for the end, but this is the biggest pet peeve of mine regarding the subject unless you want to look like a marketer sending out marketing messages, do not use capital letters in your email subjects. The purpose of email is to be personal to connect with the reader on a personal level. 

When was the last time you received a personal email, say from a friend or your mother, and the subject was capital? Never. Private messages tend to be opened more often, so keep your subjects personal.