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10 subject line formulas to boost your open rates

You have a growing subscriber list, and you’ve sent the critical promotional email that you’d been planning and crafting for so long. However, you notice that it is not getting read as much as you’d want it to.

Is your cold campaign open rate close to 1%, while the industry standards predict 3-5% as a bulls-eye? Is your warm list affording you half the open rate of what you predicted (~20% open rate)?

The invariable culprit in all such situations, with rare exceptions, is your subject line.

Nobody has the time to open and read emails with irrelevant subject lines. There are many ways to ensure that it doesn’t happen to you – the first and foremost is doing A/B testing to find out what works. However, even before you perform the A/B test, you should know what some good subject line templates have been tried and tested. 

In today’s technology-fueled world, testing and metrics measurement is not difficult. Especially with tools such as HubSpot offering you all the required facilities for performing further analysis and tests, the onus comes down to you to create subject lines and mail bodies that people would want to read. 

Let us help you with the first part of that – here are some important subject line formulas that you can use for your next mail campaign. Feel free to club multiple formulas and come up with your own – but keep the basics in mind! 

#1 – Explore the why

[Number of] Reasons to [do/use/try something]

Example: 7 ways to keep your subject lines crisp and catchy

This formula clearly states the reason behind pursuing your reader to do something. This subject line formula works well when you wish to list different benefits, features, or steps that the reader should take. 

#2 – Inquire the how

How to [get results or benefits]

Example: How to bring more people to open your mails

It’s well known and accepted in copywriting circles that titles beginning with ‘How To’ often work well – this observation extends to email subject lines. A subject line starting with ‘How To’ is effective because it promises advice or a solution to the reader. 

Keep in mind that if you wish to make this even more effective, add “This Is” before beginning your subject line. So, “How to get more people to open your mails” becomes “This is how you get more people to open your mails” – and it automatically reads 10x more impactful. 

#3 – Address pain points

[Questions around potential or current pain points]

Example: Are you finding it hard to get your emails read by more people?

Questions have an inherent power to attract readers and form instant connections – especially when the questions are relevant to the reader. Our brains are designed so that no matter what task we are up to, however focused we are, if we sense any question being asked, our attention is automatically directed to it. This happens by default – and presents a wonderful opportunity for marketers to use this context switching for best results. 

Our brains cannot handle ambiguity and uncertainty and always strive for closure. As a result of this, question-based subject lines push people to find out the answer to the question – for which they will need to open the mail! However – remember, with great power comes great responsibility. So, if you have the power to distract someone’s attention, make sure you’re doing it for good. Try to ask questions relevant to your readers and pique their curiosity, interests, and needs. This way, you will ensure that your email gets read, but you’ll also be adding some value to your reader’s life – which is the foundation of any healthy business relationship. 

#4 – Communicate direct benefits

[Benefit of solving the following challenge or problem]

Example: Higher email open rates translate to better sales.

This formula is all about keeping it direct. It’s no surprise that benefits sell, and we need to leverage that fact to achieve higher open rates. Using the subject line to communicate direct benefits that the reader can achieve on reading your email is a tried and tested way to get more people to open your email! 

#5 – Establish legitimacy with numbers

[Social proof – ideally with statistics or numbers – that the stated benefit works]

Example: Here is a list of email subject lines that boosted open rates by 70% on average. 

Social proof always influences the decisions we make. The reason is simple – whenever we are unsure of our decisions, we look around to see how others are approaching them and try to gather ideas from there. You can leverage this trait to increase open rates. The idea is to give relevant numbers or statistics to support your statement and make it legitimate.

#6 – Targeted communication and call out

[Audience/Name] + [Question or benefit]

Example: Marketers – Struggling with lower conversions and open rates? 

Sometimes, the best way to get yourself heard (or, in this case, read) is to start by targeted communication itself, no fluff! If your subject line can convince your readers that the mail is relevant to them, they are more prone to open it – and this formula ensures that happens. Such a direct approach to communication also sets the stage for clear communications in the future. 

Targeted communication can improve open rates and conversions

#7 – Take the reader on a discovery

[Discover] + [Question or benefit]

Example: Discover the direct benefits of better email open rates with these 10 subject line formulas

Use this to captivate your reader’s attention by offering them a comprehensive solution or benefits that they are looking for. This can be clubbed with other formulas by adding the word ‘Discover’ at the start of how-to or direct benefits subject lines. 

#8 – Use numbered lists

[Number]+[Ways/Tips/Techniques/Strategies] to [Achieve results or benefits]

Example: 20 ways to increase email open rate

Numbered lists have always worked. So much so that this is a go-to format, a safe bet; when you cannot come up with quick and impressive subject lines. 

#9 – Invoke the curiosity gap

What You Are Missing Out on [A benefit or pain point]

Example: What are you missing out on by not increasing your mail open rates!

What [Celebrity/Company Relevant to The Reader] Can Tell About [A benefit or pain point]

Example: What Adidas can teach you about outdoor marketing

This formula, too, leverages how our brains are wired to work. Once something invokes curiosity in us, we won’t stop till we satisfy the craving that will end that curiosity. This trick can craft subject lines for better results and higher open rates. But, and this is a big BUT – keep in mind that you are playing with your reader’s attention and emotions, so you MUST give them something worth their time. They won’t like to be cheated, and if you don’t deliver on the promise you make in the subject line, this formula can backfire! 

Making an announcement creates a sense of ‘fear of missing out’ when it goes unread

#10 – Make an announcement

New [Post/Update/Event/etc/]: [Topic]

Example: New Blog is Up: 10 Subject Lines That Will Boost Your Open Rate

This formula comes in handy when you want to announce an event, a product launch, a new website, a blog post, or anything at all. This follows the same path as direct communication and clearly states what the mail is about! 

You’re all set for your next campaign!

All the formulas discussed above stem from one core concept: helping the reader and providing some value addition. As long as you do that honestly, you can be sure to have their attention in the right places. If you’re still finding it extremely difficult to make that connection with your audience- why don’t you reach out to ContentNinja already!?

Author avatar
Shriya Garg
Shriya is the co-founder and CEO at ContentNinja. She started her first blog when she was 12 years old, and coded her first website by the time she was 14. An avid reader and writer, she published her first book when she was 16 years old and has sold over 10,000 copies since. When she's not fielding client calls, Shriya can be found cleaning cat hair from her clothes.