Improve Email Open Rate with 12 Email Subject Line Best Practices

Abraham Ernesto August 10, 2016
email subject lines best practices

Don't judge a book by its cover.

You may already have heard this quote dozens of times. But in the world of email marketing, this quote doesn't apply at all. 

Recipients DO judge an email based on its cover, in this case, is the email subject line

33% of recipients decide whether to open an email or not based on the subject line they read. 

Eh.. only 33%? That's pretty small fraction.. why should I care?

Imagine when you send out 1000 emails to 1000 different recipients. And 330 of them go straight to the trash. That's not a small fraction at all!

This is why you need to be quite careful in crafting the subject lines. 

They need to be compelling so that the viewers are willing to click the email. This means that you need to become familiar with email subject lines best practices. This way you will be able to meet the basic concept of the emails that the viewer wants to read.

Best Practices for Writing Email Subject Lines

Let's keep this simple. Let's dig in..

1. Keep the subject line sweet and short

You need to be aware of the fact that if you are in the habit of writing long subject lines, then they will cut off if they are too lengthy.

This is bound to happen if you view your emails using your mobile phone.

40% of recipients open their emails on mobile. You have to make sure that the email subject line is less than 50 characters.

2. Make use of personalization tokens

Email personalization tokenIt always bring the sense of friendliness to talk to someone who knows who we are. This concept also applies in email marketing.

When an email says your recipient's name, she will probably question who the sender is, and indirectly urges her to open the email. 

Another tactic that is bound to work well is to send location specific emails to the recipient.

3. The subject line should give a hint what is inside

The email title should reveal what is inside the email. For example, if a visitor has downloaded an offer and you are delivering the offer through the email then the subject line should be like "You latest e-book inside."

This way the recipient will get an idea that the email is relevant to her.

4. The subject line of email needs to be concise

When you are about to send an email to someone, then you need to understand the fact that people tend to scan their inbox quite quickly so the mail subject line needs to be quite concise. A complex tone will not be able to allure the recipient into opening the email.

Remember: LESS is MORE

Don't overcomplicate your message, not everyone understands complex words or sentences. Keep it simple. 

5. Use verbs that are action oriented

The subject lines tend to share a familiarity with a call to action.

Their main purpose is to attract interest that would lead to recipients to do something. In this case, is to open the email. 

This is why you need to use action verbs in the subject lines. A catchy subject email will entice the recipient to focus on the email and go on every word.

6. Perfect phrasing for the subject of your email

Well you need to make your recipient feel extra special. You can have interesting phrases in the subject line. For example phrases like, you are invited or for our loyal clients only does have an impact.

7. Create a spell of urgency

Sense of urgency

The best email subject lines are those that will be able to stop the recipient from what they are doing. 

Do you know that subject lines that create the urgency spell can lead to a 22 percent higher open rate?

Some good examples would be:

  • the offer is valid for today only
  • promotion is valid for the first 10 people
  • promotion ends in 10 hours!

Make your recipients rush to open your email to find out what you are offering.

8. Raising questions

questions.jpgA different and unique way to start the subject lines is to raise questions. 

But of course, not any kind of questions, but the questions that are relevant to your recipients. 

Some examples would be:

  • “Have you spent thousands of bucks but AdWords ROI is too low?”
  • "Have you hired countless of content writers, but none satisfy your requirements?"
  • "Do you know why your SEO campaign will never work?"

If the question appears to be compelling, then the viewer will be lured to look at what the mail is all about, and that is the ultimate objective.

9. Make use of numbers

Rather than having vague subject lines you should think along the lines of having numbers and data in the subject of the email. This greatly helps to get the email noticed.

It helps to demonstrate a straightforward and clear message about what you have to offer. It will eventually help to set realistic expectations of the recipient as well. There is no doubt about the fact that numbers help to make a catchy email subject line.

10. Adding the element of a pun to the subject line

When you want to delight the recipients, then you need to add an element of a pun to the email subjects. This will help to spice up the email and convince the reader that he has to go through the entire email.

11. Avoid using all caps

One of the email subject line best practices is that you should not be using all caps in the subject lines. The reason is that all caps gives an impression as if you are yelling at the recipient.

There is a probability that the recipient might ignore your email completely if he sees such a subject line.

12. Always make use of email subject line tester

You need to make A/B testing a routine when sending emails. This means that you need to tweak the subject lines depending upon your results. You need to understand the requirements of your audience and analyze what will work best for them.


If you follow these practices, then email marketing is bound to be a successful activity. It will take you some time and effort to understand your recipients, but it has to be a trial and error method. Eventually, you will understand what the audience expects from you.

Emails are the most effective way to reach your clients. Working on the subject lines is a mandatory activity you have to fit into your schedule. A little improvement can do wonders, and you will be pleasantly surprised to see an increasing open rate. Start implementing these email subject line best practices and see the results for yourself.