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How to Write Email Subject Lines That Get Opened

How to Write Email Subject Lines That Get Opened

Email remains one of the most instrumental tools in a digital marketing campaign. They have a more personal feel than other tactics and the highest ROI of any digital marketing channel.

However, this is only when potential consumers open them, and with the average open rate sitting between 20-40%, are you doing all you can to ensure your message is received?

This guide will look at the most important aspect that ensures an email is opened: The subject line. A small piece of content that is so crucial to get right. Below is a mix of strategies you can use; some can be used together, and some are to be used separately.

Include a Number

Similar to blog posts, how-to guides, and trivia, numbers in the subject line of an email can help to get it noticed. Combine the number with a straightforward message that will grab the potential consumer’s attention and entice them into wanting to know more.

You could go with ‘5 things you didn’t know about…,’ ‘7 reasons why…,’ ‘3 top trends…,'; odd numbers fare better than even numbers, and although the science isn’t yet telling us why this is, we so far just know it is!

Experiment with Emojis

Emojis are a great way to stand out in a mundane inbox and grab the reader’s attention. It is essential to use them appropriately and to use them in addition to written content.

If you’re a professional company working in the law, science, or medical sectors, for example, then emojis could have a detrimental effect. But, if you’re a small start-up ecommerce website, then people are coming to you purely for products, not life or death advice, so using emojis can humanise your company and increase your appeal.

If you’re unsure where to start with emojis, you can use Emojipedia for a complete list of copyable emojis.

Subject Line Length

Stick to a condensed length of around 17 – 24 characters or 3 to 5 words. This will make it easier for mobile users to read the subject, as well as for desktop users to take it in, maybe before they’ve even realised they’ve scanned it.

Although not a lot to go on, shorter can be better. Think of famous brand slogans and the ones that stick in your mind; they’re unlikely to be lengthy.

Experiment with Upper and Lower Case

The subject line needs to catch the eye of the consumer, and you can really up the chances of this by combining upper and lower case letters. Look at the sentences below and think of which took your attention first:

‘Try our Brand New product: FREE Trial,’                      ‘try our brand new product: free trial.’

Add Personalisation

If you use your database of consumers, then it is simple to add personalisation in your email subject lines to truly grab their attention and ensure you stand out from spam emails. For example, ‘Hey Name.’

Consider the Emails You Open

Take inspiration from the emails you open yourself and consider what led you to open the ones you did and ignore the others. Then use this experience to tweak your email marketing campaign.

Add Urgency or FOMO

By adding a sense of urgency to your subject line, people are more likely to take note. This could be points running out, ‘buy now while stocks last,’ ‘one day only, or ‘your free gift awaits.’ The fear of missing out and the fact that everyone loves a bargain really increases the chances of this subject line being enticing.

Provide an Irresistible Offer

Nobody wants to miss out, so by adding an irresistible offer into your subject line; people will be more inclined to open the email. Maybe this could be a flash sale, new product, free trial, or special offer with a limited window. Words like ‘ACT NOW’ can command the attention of consumers.

Don’t Give False Promises

If you have enticed your consumers with your tagline, ensure the content matches the claim. For example, if you have lured people in with the mention of a free gift, sample, or voucher, ensure this is redeemable. You don’t get a second chance to build trust online, so leave no room for your brand’s honesty to be questionable.

Time it Right

Believe it or not, the time of day matters greatly. Try sending your emails when people are starting their working day, between 8 am and 9 am; often, this is when people are scrolling over breakfast or looking for something to read on the work commute.

Another good time is midday when people are taking a break. Try to avoid weekend mornings or late evenings, as this is statistically when most emails are ignored or marked as spam.


The subject line of an email can be the key determiner in that email being opened, ignored, or marked as spam. Almost 70% of email recipients report emails as spam based entirely on the subject line, and nearly 50% chose to open an email based on this – it is essential to get it right.

Finding the balance between human and unprofessional can be difficult, especially in specific industries. The use of capital letters and emojis is something to consider to grab the attention of the reader. In addition, the time of day is an important factor in whether or not the email will be opened.

Numbers can be enticing, and with the majority of adults using mobile devices to access email, it’s worth keeping the content short. Consider slogans, alliteration, rhymes, and plays on words to draw the reader in.

Consider your own experiences as a consumer and what entices you to ‘click,’ or indeed dissuade you and use this in your own marketing campaigns. Once you have the consumer engaged, it is equally as important to ensure your email content is honest, relevant, clear, and has a call to action. The end goal is for your consumer to act.

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