Bulk email subject lines for campaign success

All the analysis and reporting into subject line length and style has proven one thing - There are no hard and fast rules when it comes to writing subject lines for email marketing campaigns.

The way one group will react to a given subject line will be different to the way another group will react, and will depend on whom you are sending to, what motivates them, how much time they have to read your email, how often you email them...the list goes on! 

Targeting and testing

No one knows your customers better than you, and with all the helpful analysis tools available to email marketers today, there is no reason why you should not be able to achieve an in-depth understanding of what your recipients respond to best. Split testing your emails is a great way see what subject line will be most effective. When you look at the results of your email subject line split test, you will not only be able to send the right message out this time around, you will also have a bit more insight into your recipients behaviour which will inform your choices in the future.

Line length

One of the greatest challenges is writing a subject line which says all you want it to within 50 characters.  There is no hard and fast rule that says your subject lines should be short or should be long, they just need to deliver the key message or proposition in the part of the message the recipient sees first. You can split test different subject line lengths to establish what works best on your subscribers.

Simple, relevant message

Simple, 'it does what it says on the tin' language tends to yield better conversion rates than mysterious 'enticing' vague subject lines. This is not always the case, but if you can avoid using cryptic or unfathomable subject lines you are more likely to achieve the metrics you want, such as high click-throughs and sales conversions. The best way to approach your style and choice of language is to keep in mind the objectives of your campaign. You are limited to space so focus on your key message/offer/proposition. Relevant and specific subject lines generally yield a greater proportion of not only opens, but click-throughs and conversions too.

Language and style

Avoid 'salesy' language. You don't need to hide the fact your email is part of a sales campaign but you should try not to use cliched phrases as these can come across as impersonal and insincere. Strike a good balance by keeping the subject line factual and avoiding the use of ‘Power Adjectives’. If you are offering ‘30% off’ then you should state it, just avoid writing  ‘amazing 30% off’ in your subject line.


Content should always come first, especially when thinking about you subject line! Be sure to write your subject line only after you have written your email message. This way you can be sure your email subject line is relevant to your email content.

Spam check

Always test send your email using a spam checker. Testing your email campaign will highlight any factors within your subject line as well as your content which could channel your campaign straight to recipients junk email boxes. The best way to keep your subject line spam filter friendly is to make avoid abusing uppercase letters and punctuation, such as exclamation marks. For example, use the word ‘free’ instead of  ‘FREE!’


There is no harm in a little bit of research - take a look at what your competitors are doing and get inspired! It is easy to sign up to a bunch of newsletters, just make sure you use a separate email account so you do not end up having to wade through them when you are working on other things! You can save the Subject lines that catch your eye in a word or excel document, ready to inspire you when you need them.


Author: Yasmin Sheikh