Crafting the perfect email subject line | Heart Internet Blog – Focusing on all aspects of the web

The following post consists of a list of ideas to play with and experiment with rather than being a definitive series of ‘must dos’; there’s nothing more important than A/B testing when it comes to emails, and we’ll be covering that later on in the series. What works for one set (or even subset) of people doesn’t work for others, so there are few hard and fast rules (listen to your audience and let them dictate by analysing their actions would be one!). With that said, here are some tips to kickstart your subject line inspiration…

Be interesting

This is the biggest challenge when it comes to writing a good email subject, not least because ‘interesting’ is subjective. Aside from A/B testing different variations to see what works well for your customer base in practice, run a small trial with a customer or target customer (this could even be a friend or acquaintance that roughly matches the traits of the people you’re targeting), and get their opinions on what’s interesting. The golden rule is to make sure that your subject lines aren’t misleading or confusing; there’s no point getting someone to read your email if they aren’t going to click through/perform the desired action at the end of it.


Use a call to action

Being clear in the action you want your customers to perform is essential, and the subject line is no different. All you have to do to take advantage of this technique is begin with a verb such as ‘Save’, ‘Win’, ‘Find’ etc. Again, this is a factor that requires testing as you may find your customers respond more to something else more strongly, e.g. their name being first, an amount of money or percentage saving, a question, etc.


Don’t overcomplicate

The most effective lines are the simple ones. Be clear, direct, and prioritise accuracy over cleverness. Confusing subject lines are more likely to get ignored or deleted; you want your recipient to be engaged and feel that the topic is relevant to them from the start.

Watch for the cut-off point

Keep your subject line relatively short to reduce the chances of it getting cut off in the mail client, especially if you have a reasonable number of mobile email users. However, you can also create a deliberate cut off point with a simple ellipsis (…) to create a specific effect and therefore enticing people to click through to find out more.

Be conscious of your tone

Use a tone of voice that’s suited to your customer base, being particularly careful about your level of formality. Most people are happy with a friendly tone; how informal you are will largely depend on your brand as well as the types of people/businesses you’re targeting and how ‘serious’ the product is that you’re selling. Slightly cheeky subject lines can be very effective in the right context, but avoid expletives and adult humour to avoid your email being automatically sent to junk folders.

Use special characters sparingly

Common symbols such as percentage signs are generally ok, but always use the correct formatting and avoid pasting them in (particularly from desktop software like Microsoft Word).


Ask questions

Whether these are directed at the customer, rhetorical, or are answered in the body of the email itself, a question is a great way to capture attention and create a sense of involvement.

Make it about them…

…never about you. People are interested in hearing about things that benefit them, which is why discount codes, money off promotions and similar offers are a big favourite. Similarly, exclusive invitations, treats, and early access all go down well.

Icons of a laptop, links, and comments

Make it personal

Communicating with individuals directly? Set up your subject lines to automatically pull through the name of the recipient and give them more personality. However, be careful about doing this if you work with a lot of businesses (as opposed to individuals) because it can sometimes end up looking more spammy than no name at all.

Be relevant

Referring to a particular holiday or time of year is great because it very rarely alienates and also highlights recency. This is particularly true around Christmas when people are more consciously looking out for email offers and expecting to spend money.


Create a sense of urgency

‘Last chance’, ‘Limited time only’, ‘Ends today’ and similar phrases can all be very effective. The main purpose is to reduce the chances of someone skimming the list of emails in their inbox and thinking ‘I’ll come back to that later’ and then totally forgetting about it. A limited time to act often drives people to action straight away.


What are your top tips for writing good subject lines? Let us know in the comments!


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