While you should direct the majority of your efforts towards prospecting and email list building, crafting catchy and effective email subject lines can also help drive your email open rates.

And, considering the whole point of sending an email is to get it opened, you should make your subject lines as unique as possible.


Ironically, emails without subject lines have an average 8% higher open rate than those with subject lines – subject lines don’t really affect open rates unless they’re spammy. This is why you should know the kind of subject lines that can trigger spam filters.

Below, we’ll walk you through the tricks of coming up with great email subject lines to ensure higher open rates and make your email marketing campaigns even more successful.

Email Subject Line Best Practices to Avoid the Spam Folder (With Examples)

Read on as we discuss the best ways that you can write catchy email subject lines to get more email subscribers and leads.

Personalize Your Subject Lines

You may already know the importance of writing highly customized and effective cold emails, especially if you want to boost conversions. The same logic applies to subject lines.

You must use the recipient’s name whenever possible and craft it according to their specific interests. According to QuickMail’s analysis, you have higher chances of success when you mention the prospect’s company name in the subject line.

It’s also necessary that you use personalization naturally, without overstepping your boundaries. For instance, always avoid using a very commanding tone. Your emails should always be friendly – something that personalizing your subject lines can ensure.

Personalized Email Subject Line Examples

  • Exclusive: Watch This Webinar for 2x Sales!

  • Thanks for believing in us, {{prospect.first_name}}

  • {{prospect.first_name}}, Get 60% Off Today!

  • {{company.name}} + 35% More =

Choose the Right Length

You only have a few seconds to impress the recipient to make them click on your email, which is precisely why your subject line length plays a crucial role.

Many recipients reject overly long subject lines, often fearing that the email will also be equally long. Plus, shorter subject lines make a better impact, as the message stands out more.

Consider the following stats:

  1. Mailchimp recommends restricting your subject line to 60 characters or nine words.

  2. Four-word subject lines have an impressive 18.26% open rate.

  3. To optimize subject lines for mobile devices, sticking to 32–43 characters is most effective.

Keeping subject lines short and sweet is a good rule of thumb. This will ensure the recipient reads the whole subject line before deciding whether or not to open your email.

Best Short Subject Line Length Examples

  • Don’t Forget! Our Podcast Launches Today

  • Double Your Sales Right Away (Your First 3 Steps)

  • Tonight only: A customer’s dream comes true

Leverage FOMO

Despite being a millennial lingo, FOMO, or fear of missing out, applies just as much to adults. You‘ll find most subject lines create a sense of urgency, a tried-and-tested tactic used by email marketers to inspire action from the recipient.

You have to use the right words – and in the right order — to get your audience excited. The good news is if you do this effectively, you can expect a 22% higher open rate.

Here’s a list of words that you can use:

  • Hurry while offers last

  • Save 30% right now

  • Exclusive

  • Last Chance

  • Act now

The idea is to communicate urgency and create scarcity so recipients are compelled to click on the email. At the same time, you don’t want to cry wolf, which is why you should reserve urgent-sounding subject lines for genuine occasions.

Urgent Email Subject Line Examples

  • Act now or regret later, {{prospect.first_name}}

  • Final Reminder: The Mega Amazon Sale Ends Today

  • Limited Time Offer to Get MAC Cosmetics at 50% Less!

Sentence Case, Title Case, or Lowercase?

Deciding between title case, sentence case, and lower case is a struggle for most marketing professionals. Before we discuss the suitability for each, let’s re-acquaint you with what these three types mean:

Title Case: This Is Where You Capitalize All Major Words.

Sentence Case: Here you follow the regular capitalization rules – similar to writing a normal sentence.

Lowercase: you don’t use any capital letters for lowercase – at all.

While this may seem irrelevant, your chosen case directly affects your open rates. Most studies have found that title case subject lines have a higher open rate than the other two types.

Use Emojis, Albeit Wisely

Emojis make you appear friendlier, be it on social media, LinkedIn, WhatsApp, or your subject lines.

Since the point of sending cold emails is to kickstart conversations, emojis deserve your consideration as they add friendliness and visual appeal. And why not? They are expressive and can help communicate interesting concepts – all while taking up only a single character.

However, you need to consider your target audience and industry niche.

We wouldn’t recommend using emojis if you have formal or upscale branding, but if you’re targeting young, informal adults, emojis could be helpful. A/B testing your subject lines to see how your audience reacts to emojis.

Email Subject Line Examples With Emojis

  •  Join our first-ever warehouse sale

  • Happy birthday, {prospect.first_name}!

  •  +  +  =

These are the best practices for creating effective email subject lines that can work in your favor.

Cold Email Subject Lines Mistakes To Avoid

We covered good practices to incorporate when writing subject lines. Now, let’s focus on the don’ts of subject lines.

Using All Caps


Ditch shouty capitals to avoid intimidating or otherwise putting off your recipients.

Using ALL CAPS doesn’t look polite, and it’s also highly likely it will cause your emails to end up in the spam folder. And if it does make it through the spam filters, you‘ll certainly not earn any brownie points with your reader.

Avoid Sounding Spammy

Do your best to avoid using spam trigger words when writing your subject lines. This includes commonly used words like “free,” “100%,” “earn money,” “extra income,” and “congratulations.”

Hubspot has compiled a list of potential spam trigger words you shouldn’t use when writing an email subject line. Another tip would be to think from your recipient’s point of view — this is why authenticity is so important.

Use Punctuation Wisely

No matter how tempting it might be to add more exclamation points, you must resist. More so when one is enough to increase your open rate by up to 20%.

The general rule of thumb is to never include more than two punctuation marks. Otherwise, you might end up getting flagged, earning your email a trip to the junk folder.

Avoiding Silly Mistakes

When it comes to writing good subject lines, silly mistakes can include spelling and grammatical errors as well as botched customer segmentation. While you can prevent the former by using tools like ProWritingAid, you have to do a bit more research for the latter problem.

If you properly segment your emails, more email recipients will open your email. This is mainly because you’ll be able to personalize your subject lines by catering to your recipients’ preferences and expectations.

Good Email Subject Lines Means Higher Open Rates

Getting for subject lines right does increase the chances of adding more email subscribers to your list and scoring more convergence. Since a person receives hundreds of emails in a week, being a little creative can help you make an instant impression.

Along with your subject lines, make sure you are on the right track for ensuring a successful cold email outreach. Don’t forget to sign up for your free QuickMail trial to maximize your sales.