9 Proven Tips for the Best Email Subject Lines

Did you know that approximately 35% of email recipients open an email based on the subject line alone and that 69% of email recipients report an email as spam solely based on the subject line (via ConvinceandConvert)?!

The lesson is clear: if you want higher conversion rates, more leads, loyal customers, and an above-average ROI on marketing efforts, you’ve got to be using the best email subject lines.

What do you get out of being an eCommerce merchant that uses the best email subject lines? You can be part of the 55% of companies generating over 10% of sales from email – eCommerce companies need to be the ones leading the way!

To make sure you get higher open-rates on your emails, here is an awesome list of proven tips and tricks for writing the best email subject lines.

1. People are curious by nature

We keep moving forward, opening new doors, and doing new things, because we’re curious and curiosity keeps leading us down new paths. – Walt Disney

What’s the connection to email subject lines? We don’t open all of our emails. Which ones do we open? First, and foremost, we open emails that have subject lines that make us curious and hence desiring more information. In email marketing, using words that signify “discovery” either in the form of a statement or a question, are curiousity builders.

Take me for example. I love all things marketing. When I open my inbox, there are many different subject lines – some good, some bad, and some great. I never delete an email with a subject line that tries to explain something or asks a question.

curiosity for best email subject lines

  • Why [name] buys from [your company]

  • How [your company] got its name

  • What can you buy for [price] at [company name]?

  • Want [discount rate] off your next order?

  • Did you forget about [sale/coupon code]?

  • Why we don’t  [___]

  • The reason why we [___]

2.  We are attracted to numbers more than words

Have you noticed that more and more blog posts use numbers in titles? The same trend is going on in email marketing, if you haven’t noticed. According to research by the Content Marketing Institute, blog posts with numbers got opened 45% more often than not. You can expect similar a worth-while increase for your emails too.

Look at my inbox. Do the numbers not stand out?

numbers for best email subject lines

  • Top [x] [product] under [$x]

  • [x] days until [___]

  • [x] products being bought at a ridiculous rate

  • [x] gift ideas for [__]

  • [x] reasons to start [__]

3. Use authority figures

When kids are in their teen years they don’t like authority figures and try to rebel. Well, when it comes to email, authority figures can be game-changers. When a company mentions Google or another very successful (or unsuccessful) company in a headline, it grabs our attention.

The reasoning is simple. We don’t expect to see that and it makes us hungry for more. For instance, I recently received an email from Amazon, and in the subject line they mentioned The New York Times. If you think that the hundreds of thousands of people subscribed to Amazon’s email list opened that email, you are right. What types of “authority” are currently trending? That’d be pop-culture references – something that can work extremely well for any eCommerce merchant.

  • You can dress like [___] too

  • [___] just bought what from us?

  • How you’re helping us become the next [___]

  • The [___] guide to [__]

  • Our [product name] is as cool as [___]

4. Opposites attract

Usually you hear this saying when people talk about relationships. Luckily for us, this also works extremely well in email marketing. Like numbers, explanations, and questions, email subject lines that use 2 opposite words can stand out – in a good way. Refinery 29 made waves with this subject line: The broke girl’s guide to a luxury vacation. Usually broke people don’t go on luxury vacations – but to every rule there can be exceptions.

  • 5 Luxury products that anyone can afford

  • What you can learn from [____] on [____]

  • [x% off] only today (and tomorrow)

  • Our [___] is like [___] but better

5. Huge discounts just don’t work…ever

Who doesn’t like free things? It turns out that email subject lines that use “free” get opened 10% more than those without. Is “free” the only pricing discount that’ll lead to a higher email open-rate? Fortunately, for all eCommerce merchants (and everyone else) the answer is no.

Below is a table that was created by Adestra

Adestra's discount rates for best email subject lines

You can clearly see that 10% discounts perform better than others – even those that are double the size. To strengthen that point – for the doubters – we too found the same trend:

Although a 10% discount had a better ratio of visitors to sales than 5%, when the discount got any higher the ratio actually got worse! Now that’s sensational! Instead of rising as expected, the ratio of visitors-to-sales decreased, i.e. the bigger the discount was, the lower the sales per visitors were.StoreYa Blog, Finding the Discount Sweet Spot

6. Urgency works

When an offer is urgent it gives off a feeling of exclusivity. Think about it. If someone tells you that the sale is ending tomorrow or that tomorrow something starts, even if it is not just for you, it certainly makes you feel like you’ve got an exclusive offer.

The best email subject lines that drive results for eCommerce merchants are the ones that use urgency better than the rest. It has been shown that an email subject line that creates a sense of urgency and exclusivity can lead to a  22% increase in open-rate. Here is a great table that puts things into perspective, via Marketing Land.

Via Marketingland Urgency best email subject lines

Overusing any of the aforementioned words can have a negative effect on email open (and read) rates, if the same word is used constantly or if the email’s content doesn’t live up to the keyword’s presence.

Heard of the halo effect? This “effect” is a cognitive bias that influences a person’s feelings toward a company/brand/product based on their past experiences and impressions with that entity.

7. Names lead to success

To make the email subject line more appealing, use names. This includes using your company name and also the subscriber’s name.

Check out the first few rows of something neat that MailChimp created. All of the successful subject lines included the company’s name.

Mailchimp openrates best email subject lines

Need a few more ideas? See the entire table that MailChimp put together.

  • New [___] at [your company]

  • Why [person’s name] is awesome

  • New and Improved: updates from [your company]

  • [Your company]’s latest online catalog

  • Something’s new at [company name]

8. Sales are just one part of the equation

We all want to sell more – and that is great. However, the subject line is not always the place to do that (unless something is free or 10% off!). Instead, the best email subject lines, as outlined here, and seen in MailChimp’s table, don’t come across as a sales pitch.

The subject lines that bring great results are descriptions of the email’s content. Trying to sell something can lead to using words that spam filters hate, leaving you in the spam filter, and not in front of your email subscribers.

See a few examples of descriptions that work.

  • JetBlue: You’re missing out on points

  • Eater Boston: Where to Drink Beer Right Now

  • HubSpot: Here’s a blog calendar template to help you schedule upcoming blog posts

  • Weebly: New themes and fonts are here

9. No clear-cut answer for subject line length

There are studies that point to shorter subject lines working and there are also studies that show longer subject lines work. There is no one recipe for subject line length. However, because more and more emails are read on mobile devices, you should definitely make sure that your keywords and/or call to action comes earlier, rather than later.

Yesware’s studies have shown that email open-rate is not influenced by the length of the subject line.

YesWare graph email subject line length

Friendly Reminder

Know your audience. It is a simple concept, yet something that is too often forgotten. This is a rule for everything you do in business, and not just for your email marketing. Try to create a list of traits and reasons as to why people are on your email lists. By knowing who your audience is and what their tastes are, you can create subject lines that lead to more opened emails every single time.

If you truly know your audience then you’ll also know what keywords work and which ones won’t. For instance, if my list is comprised of industry leaders then, more than likely, the word “secret” will probably be less successful in achieving a higher open-rate than the word “proven”.What Mashable or BuzzFeed write in their email subject lines don’t necessarily fall under practices for the best email subject lines that work for your audience.

Know who you’re writing to, and then start testing which keywords work and which ones don’t.

Ty Rothstein

Ty is a digital marketing enthusiast that can't get enough social media marketing and content marketing. He is the inbound marketing manager at StoreYa where he spends his days searching for the newest social marketing scoop and creating amazingly awesome content. If you’d like to chat with him, feel free to connect with him on any social platform.



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6 Responses to 9 Proven Tips for the Best Email Subject Lines

  1. candice says:

    Ty Great article, thanks for packing in so much Value, Email subject lines are definitely something I want to work on. Thanks for sharing

  2. Numbers are too good to pass up Ty 😉 My number subject lines do well; especially if they are double figure numbers. Really smart tips!


  3. Niraj says:

    Excellent article, Ty. Great tips, my pick – creating a sense of urgency. When combined with personalized subject lines, it will definitely result in higher open rates. Thanks, Niraj (Founder at grexit.com)

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