Subject Line Best Practice: 5 ways to write better email marketing subject lines

For most users, the email inbox is a busy place, with a stack of emails screaming out to be opened. In this kind of environment, it’s essential to make sure your subject line is compelling and demands to be opened. After all, no matter how pretty and well built your email campaign is, if your subject line is monotonous and uninspiring then none of your recipients will look at it. These 5 tips have been proven time and time again to significantly boost your open rates and overall conversions from your email campaigns:

An inbox, yesterday
An inbox, yesterday

Tip #1: Add personalisation

Think about what data you have to hand, and how it can be implemented into the subject line. For many marketers, adding the recipients’ first or surname often boosts open rates.

Tip #2: Avoid spammy words

This is a given, both in the subject line and your email copy. Don’t include multiple exclamation marks, multiple dollar signs, all caps text or words like “viagra”. There’s lots of differing lists of spammy words – check with your email sender as they’ll have the most accurate insight.

Tip #3: Focus on the benefits

Tell people why they should open your message – outline your key offer and tell them how it will benefit them. Of course, you should always make sure your subject line relates to the content of your mailing. If users feel tricked into reading your email, at best they won’t be back, and worse they’ll mark your email as spam.

Tip #4: Use pyramid writing

Most email clients cut off subject lines somewhere between 40 and 60 characters. In addition, users scan subject lines from left to right, so it makes sense to put your key offering right at the start. For example “Buy a new toaster in our sale and save 50%” won’t be as effective as “50% off toasters in our sale”.

Tip #5: Test test test!

As with all best practice, everything is only theoretical until you’ve tested it with your specific company, market niche and recipients. Testing what works and constantly refining your subject lines is the best way to guarantee a result.

Bonus Tip: Sometimes longer is better

In some instances, particularly long newsletters with lots of offers and content, a long subject line can function as a contents section. Most email clients will still cut off the subject line after 60 or so characters, but once the user opens the email the full subject line is displayed – and it’s suggested that this is what they’ll read first. Regardless, it’s still worth optimizing those first 60 characters.

Money Saving Expert's long subject line acts as a contents section
Money Saving Expert's long subject line acts as a contents section

Bonus Tip #2:  Sender name and pre-header

There’s two other tools you have at your disposal before a recipient opens your email. The first is the sender name and your sender email address – these should be consistent and reflect your brand name. In some situations, if you’re running a regular mailing you could also incorporate the name of your newsletter into the sender name. The other tool you have, which applies in certain email clients such as Outlook 2007 and Gmail, is the pre-header or Johnson Box.

More Resources

The Perfect Email Preheader (aka Johnson Box)

This blog post is about how you can improve your email marketing performance by including a quick summary right at the top of your mailing.

See that there? It’s the first thing you read and it gives a quick summary of what this piece is about.

Used correctly, the Johnson Box will raise more than a smutty chuckle from your creative department – it’ll raise open rates and click throughs on your mailing. The Johnson Box, by the way, is a relic of old school printed DM – you can do your homework on Wikipedia. Sometimes also referred to as a Preheader, it’s recently seen a resurgence in email marketing circles.

An example of a Johnson Box in a retail email
An example of a Preheader in a retail email

So why should you use a Preheader and why does it work?

It gets the key offer into the preview pane

The chances are that at least some of your recipients don’t have much time and want to go straight to your key offering, as quickly as possible. When used correctly, this will get your key message right into the most prominent place on your email, and combined with a link or call to action, it’ll direct users exactly where you want them.

It works when images are turned off and on mobile devices

Sometimes the bulk of your mailing may not display correctly because the user has images disabled, or is using an email client or device that has HTML rendering issues. We’ve talked about the rendering challenges of email clients before – but it makes sense that adding the key proposition of your campaign to the top of your email will ensure the message gets across.

It boosts the subject line

In some email clients the text right at the top of your email is displayed before the recipient opens the mailing. For example in Outlook a small box often appears above the system tray, and in Gmail the first line of text often follows the subject line in the inbox view.

In Gmail the Johnson Box copy is added after the subject line
In Gmail the Preheader copy is added after the subject line

It reduces spam complaints and helps deliverability

One of the most important ways ISPs determine your email reputation is from how many users click the “this is spam” button. Giving your users a clear and succinct overview of your mailing, explaining why it’s relevant to them helps them quickly understand what it’s about and means they’re less likely to mark your mailing as spam.

Does It Work?

Yes! We’ve implemented preheaders on a number of campaigns and it’s raised open rates, click thrus and reduced spam complaints.

The Perfect Preheader

There’s plenty of things to test here, but generally these are the best ways to add implement a Preheader:

  • Place right at the top of your mailing, before the link to the hosted version or any kind of whitelisting copy
  • Include the key offer, benefit and message of your mailing
  • Include a link to the main offer landing page and a text call to action (eg. Find out more)
  • Keep it short and snappy – less than 30 words, 20 if possible
  • Try adding personalization
  • Don’t repeat the subject line but do think about how they can work together.

Want to read more? check out our tips for writing email subject lines.

Using Twitter to find the best time to mail your Email Newsletter


There’s an interesting idea on Toddle’s blog about using Twitter to find out the best time to send your mailing based on what time and day there is the most chatter about your brand, product or market niche. It centers around grabbing the RSS feed of a Twitter search, and running it through Google Reader in order to get some tangible statistics around post frequency.

I know online experts will fret over the best time to send an email newsletter until the cows come home, and the reality is that even if there is a best time then it’s definately different for every list, client and even product range, but this is still an interesting bit of insight and it’s very simple to get hold of, good work!