What to Write In a Subject Line to Attract Attention

Why are subject lines necessary

The subject line is the first thing a person sees after receiving an email. At times, it becomes a deciding factor whether the email gets opened or not. Therefore, the subject line must be catchy and easy to understand at a glance.

In email marketing, the subject line acts as a storefront. You may prepare great content and thoughtful offers, but if the subject line doesn’t "hook" your email recipients, all the work will be in vain since without opening the email, no one will know what's inside.

A good subject line should not confuse or bore the recipient. Its purpose is to provide the recipient with a reason to immediately open this email. For example, this could be a specific benefit ("30% off everything until this evening"), a personal appeal ("Happy birthday, {name}"), or simply something catchy that sparks interest.

Email recipients read emails quickly, often in between other routine tasks, and they don't have the time to figure out ambiguous subject lines. If an email is simply titled "New Information", the chance of it being opened is minimal.

The subject line sets the tone for the entire email. It can be formal, friendly, or intriguing — as long as it suits the content and piques interest. And, of course, don't underestimate the value of testing: sometimes, changing a few words in the subject line results in a significant increase in email open rates.

How to write a good subject line

How long should the subject line be

When someone scans their inbox, they do it quickly, without reading carefully. Their gaze simply sweeps over the headlines. If the subject line is too long or convoluted, it gets lost among other emails. This is especially true for mobile devices: a long subject line won’t display completely on a small screen.

Is personalization required in the subject line

If an email addresses a person directly — by name or by mentioning something relevant to them — it is perceived as more valuable. Yet it’s important not to make it too trivial. Simply adding a name to the subject line doesn’t automatically make the message special, and if done in every email, it can become tedious.

Personalization works when it is appropriate, such as when you’re congratulating someone on a holiday, reminding them of an appointment, or sending something related to a specific action of the user. In these cases, the recipient's name or other personal details in the subject line feel natural.

It's also important to understand who your audience is. Young people tend to react well when seeing a name without formalities. However, when sending an email to adult individuals, it’s better to show respect — for instance, by including their full name.

Should you use numbers in the subject line

Numbers in the subject line make it much easier for the recipient to understand what the message is about and what to expect. Numbers can be used to represent the size of a discount, a price, the duration of a video, the number of tips, or anything else that can be expressed with their help.

However, it is important that these numbers are reasonable and eye-catching. The main thing is not to overload the recipient: for example, if the document attached to an email has 50 pages, this can be off-putting, yet 8-10 pages seem more accessible.

How mysterious should the subject line be

It’s not always necessary to lay everything out in the subject line immediately. Sometimes, it’s better to keep a bit of intrigue — provide a small hint on what awaits inside the email, ask a question, or simply write something that provokes interest. The main mechanism behind this approach is human curiosity: if the subject line provides some sense of mystery, this awakens the desire to open the email and figure out what this is all about.

The key is not to overdo it. Such intrigue should evoke interest, not irritation.

Should mistakes be acknowledged

If something went wrong, it’s better to acknowledge this right away. You may highlight this directly in the subject line instead of trying to sweep it under the rug. Readers appreciate when they are spoken to directly. It shows that there are real people behind the mailing, not a soulless mechanism. Moreover, stories about failures are often read more eagerly than it might seem — simply because there’s something real and relatable in them.

Is it okay to scare readers

Sometimes, it helps to spark interest slightly, to let the readers know that they might miss something important if they don’t open the email. Yet once again, it's important to know the limits. If you push too hard or scare the audience, the email will simply be left ignored. However, a light hint of urgency may attract attention.

Also, don’t deceive the readers. If you already informed them about cutting off access from May 1st, don’t send them a message later saying "We will close access from June 1st!!!".

Should you entice readers with gifts

If you’re sharing something interesting in the email — for example, a link to a video, a useful instruction, or a visual diagram — it’s worth making that clear in the subject line. This way, the recipient immediately sees that the email was sent for a reason and that there’s a specific benefit awaiting inside.

At the same time, it’s important not to overuse words like "free" or "as a gift". They sound attractive, but email clients tend to regard such subject lines with suspicion. If overdone, the newsletter might end up in the spam folder and never reach the reader.

Can you make the subject line flattering

Sometimes, a simple technique like letting a person know that this email is not for everyone works best. For example, you could mention that the recipient is granted access to a "secret" offer or that special conditions apply.

When the recipient sees that they are treated in a special way, interest arises: "What’s in it for me? Why was this sent to me?".

Are quotes appropriate

In most cases, there’s no need to come up with something complicated to make the subject line stand out. Simply using a familiar-sounding phrase can be enough. This could be a line from a song, a quote from a movie, or just a common expression used in everyday life. Since these are highly recognizable, such things immediately catch the eye.

For instance, if it’s the sale season, you may play on seasonal associations, like "Spring is coming — prices are melting".

Such subject lines are not irritating because they sound familiar and friendly. Plus, if you add a bit of irony or wordplay, this creates a sense that the email is crafted with care.

Are emojis effective in subject lines

A small image has the power to convey more than several words. Emojis, emoticons, and even simple text smileys can enliven the subject line and make it stand out in the inbox. Readers are accustomed to such symbols in messaging apps, and if used appropriately (and moderately), the email appears warmer and more lively.

Emojis can emphasize the meaning of the subject line and immediately convey what the email is about. The main thing is to choose them appropriately. Don’t insert symbols just for aesthetics: make those related to the content.

Even if your newsletter is formal, this doesn’t mean that you should shy away from using emojis. You may find suitable neutral options: for instance, a graph would be good for a report or statistics, while a pin could serve as a reminder about an event.

In some cases, emojis can conveniently abbreviate the text. For example, instead of a phrase like "the package has been sent", you may use a box icon, an arrow, and a door. This makes it short, clear, and noticeable among other emails.

Mistakes in subject lines

Conclusion

The email subject line is the first thing the recipient sees, and it’s where the contact begins. It affects whether the email will be opened or go unnoticed. A well-crafted subject line should be short, specific, and clear. It reflects the essence of the email, sounds appropriate, and doesn't cause irritation with excessive emotions or pressure.

When working with subject lines, it’s important to rely on common sense, knowledge of your audience, and the real goals of the email. It’s a simple element that directly impacts the success of the email campaign.