The Importance of Subject Lines in Emails

On June 03, 2020
8min read
Olga Mykhoparkina CMO @Better Proposal

There are 3.9 billion email users worldwide. This means that one in every two people on the planet use email. In contrast, only 0.4% of the human population used the internet back in 1995 which shows stunning growth.

Beyond widespread internet use, the popularization of emails has also been driven by marketers who are trying to generate leads and close deals through their sales emails. Sadly, less than a quarter of sales emails are even opened.

If you want to get the most out of your sales emails then you need to optimize every single aspect of it, especially the subject line. Emails that have poor subject lines won’t get any traction, even if the information contained within is more interesting.

Read on to become a master artisan of subject lines.

Why are subject lines so important?

The subject line is the first thing that recipients see when they get your email. This is why they must be brief, catchy, and informative if you want to get favorable open rates. Subject lines are the introduction that recipients use to gauge the intent of the email.

Seeing as most inboxes are bombarded with spam mail, newsletters, and marketing offers, you’ll need to find unique, relevant subject lines to have any chance of recipients reading your message.

You could have the best email in the world with a world-class CTA and it still won’t make you any money if recipients aren’t reading it. Think of subject lines as your chance to appeal to the recipient’s needs in a few words.

5 tips to write an effective subject line

The first words that the recipient sees will have an impact on how they perceive the rest of the email and what impact it will have on them. If you want recipients to not only open but also act on your email, you need a highly effective subject line. Here are five tips that can help:

#1 — Establish urgency

The act now!” subject line is overused and nothing more than a running joke at this point. Still, it does remind us that instilling a sense of urgency in subject lines is an important part of boosting open rates.

A better approach would be “70% off for the next three days” since it gives the exact figures rather than being vague. “Our annual plan is half-off if you subscribe within 24 hours is also a good option since it provides key information while staying concise.

It’s essential that you only use this tactic when the offer is indeed limited to a specific time frame. If you rely on false urgency to get your emails opened, then your mailing list will eventually catch on and start unsubscribing.

#2 — Curiosity

Adding some mystery to your subject lines can hook recipients in and ensure that they read your email all the way through. You should still keep it relevant to your target audience even when being enigmatic so that they don’t think your email is just another piece of spam.

Something vague like “you’ll benefit if you read this” could come off as an impending scam whereas “this industry secret increased conversion rates by 24% in 24 hours” will get better reception since it’s more relevant to the mailing list’s area of interest.

#3 — Star power

Celebrities, political figures, and athletes all have a large following. You can leverage this interest to your advantage by mentioning popular influencers in your subject line. Did Kim Kardashian recently tweet about your company? Let your mailing list know that!

You should be cautious to avoid controversial personalities though, particularly with regard to politics. Touting conservative support for your business may deter liberal consumers and vice-versa. Never alienate any prospects as that will shrink your potential market.

#4 — Conciseness

Up to 77% of all email opens are done on mobile devices. This number could be a bit lower depending on your industry but you should still factor in the smaller screens that most recipients will be viewing your emails on.

Try to keep your subject lines under 50 characters to ensure that the full message fits on their screen. Shorter subject lines are also more likely to be read by recipients since it won’t seem like a chore to understand.

Enjoying this Post?Join Our Newsletter

Only the best content, delivered once a month. Unsubscribe anytime.

#5 — Retain humanity

With the rise of AI technology in all industries, more people are skeptical to open emails since they think it may have been sent by a bot. Using human email addresses like will show them that the message was sent by a real person.

Be sure to tailor your sign-off accordingly. It would display a noticeable level of inconsistency if the email address sending the message is of a specific team member but the sign-off reads “sincerely, the sales team.”

Subject line examples

We believe in the watch and learn doctrine, so here are examples of effective subject lines:

Company name

As you can see, Autoklose favors simplicity in this template. There are many benefits to taking such an approach with your subject line. First of all, keeping it short means that recipients will be more likely to read it.

When faced with an excessively long subject line, some recipients may just ignore it altogether. Mentioning the company name in the subject line also shows them that the email is personalized to them rather than sent out en masse to every company in their industry.

It also puts your brand name in their head from the get-go before they even start reading the email itself. This can boost your brand awareness even if they don’t read the email all the way to the end.

Breaking news

Another popular strategy when crafting subject lines is to tap into human curiosity by opening with an intriguing news story. This will hook the reader in and ensure that they open the email. Be sure to deliver with key details and cited sources so they don’t feel baited.

Once you’ve satisfied their hunger for developing stories, end with a call to action. These types of subject lines are more likely to be opened than vague or repetitive titles.

Special offers

Special offers are a great way to generate interest from your existing customers or even acquire some new ones. It may seem counterproductive to lower prices for new customers but it’ll pay off in the long run since they’ll continue to use your service even after the discount rate ends.

That being said, your special offer won’t grow your userbase if the subject line falls short. You should summarize your offer in the subject line so that recipients know that the email is worth clicking on.

It’s also advisable to emphasize key parts of the offer such as free or limited-time by capitalizing it — as seen in the example above. It might seem cliche but capitalizing those crucial points will help them pop out and highlight the essence of the whole message.


You might want to consider automating your email campaigns to get the best effort-to-return ratio. This will save you a lot of time and money while garnering better results in the process.

By using automation software, you’ll be able to send emails out in greater scale — leading to a larger sample size of data to analyze. This will make your split testing results more accurate when comparing different subject lines.

Automation also makes it easier to divide your customer database into multiple groups then send segmented emails that are better tailored to each recipient. It may take a bit to set automation up but it’ll be well worth it in the end.

What to split test for in subject lines

Split testing is essential when trying to optimize your subject lines. The best way to find the ideal subject line is to try out multiple variants and see which ones have the highest success rate. Here are five things you should split test for.

Name vs. no name

While it’s true that adding a name to the subject line does generally improve results, there are certain mailing lists that will respond to it differently. Try both variations and see which ones yield a better outcome.


Testing first-person, second-person, and third-person subject line perspectives will provide valuable insight. Compare the results and see which perspective your subscribers react to best.  In general, subject lines with “you” in them tend to perform marginally better.


Another thing you can split-test for is the length. 6-10 words mark the Goldilocks zone but you can still try shorter or longer variations to see if any of them perform better. Most subject lines see a drop in open rates as they get longer though.

Emojis 🙂

It may seem counterintuitive to insert emojis into business emails but they can actually have a positive effect on your campaigns. This is especially true if you’re targeting younger demographics. Split test different emojis against control subject lines without emojis.

Sentence Case vs. title case

This debate comes down to preference for many marketers but the majority of large brands lean towards sentence case subject lines. If you don’t have a strong preference for either one then you can test both of them and see which variant your subscribers engage with.

Tools to test subject line

Writing subject lines is all well and good, but that’s only half the battle. Before you send them out to customers, you should test them with tools to ensure that everything is up to par. There are quite a few tools that can help with this, and the ones below are some of our favorites.

You should pick your tools depending on the volume of emails you send each month, which features you need, and the platform that you find the easiest to use. At the end of the day, you’re the most qualified person to pick which solutions suit your needs.


The first tool on our list is Mailtrap. It’s a fake SMTP server that you can use to test your emails in a controlled environment before sending them out into the wild towards real inboxes. You can think of it as a sandbox that enables trial runs for emails.

One of the best parts about Mailtrap is that it can help you avoid spam filters. It does this by giving your email a spam score between zero and five. If your spam score is too high then it will guide you on how to edit your email and bring the spam factor down.

Mailtrap has a free plan that lets new users test out its functionality before committing to a paid subscription. This can help you gauge whether or not it’s the right tool so that you don’t waste your hard-earned cash on something that isn’t the right fit.

Once you’ve determined that Mailtrap is indeed the tool for you, it’s time to choose between their five paid plans. Prices range between $9.99/month to $299.99/month depending on your needs — with the enterprise tier offering near-limitless functionality.


Next up we have SendPulse. It’s the perfect tool to use when you’re experimenting with subject lines since it lets you easily split test. Now you can create multiple versions of every subject line idea and see which one yields the best results.

SendPulse can also help you personalize your subject lines. You can factor in pieces of information like their location, gender, and even name to ensure that you have the perfectly tailored subject line for every recipient.

By using the SendPulse software, you’ll be able to send different text depending on the details of subscribers. This is especially useful when trying to reference celebrities in your emails since it wouldn’t make much sense to mention a Brazilian actor when messaging someone in Dubai.

Increasing relevance and personalizing emails will lead to a massive boost in engagement when running your email campaigns. The tool also gives you access to a gallery of over 130 email templates that you can use in conjunction with your newly-perfected subject lines.

The best part is that SendPulse is free if you have less than 500 subscribers on your mailing list. Those with mailing lists between 500 and 1,000 subscribers will be paying $12/month. Billing annually will cut costs by 35%.


Pricing scales with volume, but you can cover 16,000 subscribers for as low as $50/month.



Last but not least, Touchstone — a subject line tester that can get you results in a matter of seconds. It can handle lists with over 250,000 subscribers, making it the perfect tool for large companies who are trying to optimize their email campaigns.

The results will cover the delivery, open, and click rates since all three are paramount to the success of your email campaign. It even lets you set up A/B tests in 30 seconds which is far faster than the 15 minutes to one hour that you’d normally spend setting everything up.

Touchstone gets these accurate results so quickly by simulating your entire subscriber database and running it through their proprietary algorithm to forecast how your subject line will be received.

You might be concerned about accuracy, but Touchstone’s algorithm can predict the performance of open rates while only being off by 1-2%. That’s astoundingly accurate when measuring something that can vary depending on human behavior.

There are three paid plans to choose from when using Touchstone — essential, expert, and enterprise. These plans cost $69, $99, and $297 respectively. The three-tier pricing system makes the tool accessible to companies of all sizes.


As you can see, producing high-yield subject lines doesn’t have to be rocket science if you apply some tried-and-tested core principles. Email marketing isn’t going away anytime soon — seeing as every dollar spent on it brings a $44 ROI — so you might as well get familiar.

According to Fluent, Inc., 42% of consumers will likely visit a brand’s website after receiving an email from them. This means that even if they don’t bite on your email’s main CTA, they could still end up engaging with other offers from your company.

That’s all for now, happy marketing!

Article by Olga Mykhoparkina CMO @Better Proposal

Olga Mykhoparkina is a Chief Marketing Officer at Better Proposals, an easy-to-use proposal software that helps send professional proposals in minutes instead of hours. She’s a SaaS enthusiast with entrepreneurial mindset, a deep SEM expertise and 10+ years of experience in digital marketing. Having written for 50+ top tier publications, she believes that epic content is King, Queen and all the Aces in marketing.