5 Easy Subject Line Tester Tools to Increase Email Open Rates

April 20, 2018 | By | Live Chat, Marketing
5 Easy Subject Line Tester Tools to Increase Email Open Rates

Email marketing, if used correctly, can prove to be one of the most effective tools to promote your business. The very first hurdle is the most crucial one to cross – getting prospects to open your mail without either ignoring it or just deleting it outright. It is only when you are through this all important stage, does your email stand a veritable chance of creating the desired impact.

In short then, much of the efficacy of the email depends on the allure of the subject line – whether it is arresting enough to capture interest and entice your potential customer to open and read further. What this means is that your subject line must stand apart from the rest of the usual clutter in the inbox. How do you ensure this?

This is where Subject line tester tools come into the picture. By testing the various elements of your email, you can observe the impact on customer behaviour, and understand if there is a pattern you can follow to boost open rates.

But before we elaborate on the tools, here is a brief synopsis of 5 of the best Subject line tips you could use to maximise their chances of being opened.


  • Creating a sense of urgency – Adding a limited time frame for an offer or sale often succeeds in piquing the interest of the reader, inducing them to open the mail.
  • Nurture a relationship with influencers relevant to your audience – Leverage the popularity of social media influencers by including their name in the subject line (you will need their consent on this for sure).
  • Customise the email with personal recommendations – Simply adding “Just for You” could go a long way in striking the right chord with your leads.
  • Generate curiosity with numbers and lists – “Top ten” lists have become the new favourite among readers as they attract interest and promise a quick, enlightening read.
  • Offer a free gift without using the word “free – Instead be specific and let the reader know of the value that has been offered – say a discount of $50.

Now that we have skimmed through some useful tips on how to frame the best subject lines, let’s get to the main topic of this blogpost.

5 Easy Subject Line Tester Tools to Increase Email Open Rates

If you wish you had a special knack for being able to come up with witty lines at the snap of a finger, you are not alone. Fortunately, there are tools available today to help you write clever, eye-catching lines at the click of a button. Below are some of the easiest Subject line testing tools you could choose from.


1. Test Subject by Zurb – Price: Free

This tool gives you an instant preview of how your subject line, pre-header text and sender name will appear on popular mobile devices.

2. Email Subject Line Grader by Net Atlantic – Price: Free

This provides you with a score on how gripping your subject line is and even gives you suggestions on how to improve it. It also checks the word and character count and analyses how it measures up on the action and emotion quotient.

3. Spam Check – Price: Free

The worst fate an email can meet is getting relegated into a reader’s spam folder. This tool identifies words/terms that may trigger spam filters to trap the emails. You could then modify your copy to steer clear of those terms.

4. Emotional Marketing Value Headline Analyser – Price: Free

Get insight into whether your subject line resonates with the intellectual or empathetic side of your brain and also understand which aspect you should target keeping in mind your goal.

5. Email Subject Line Keyword Checker by Adestra – Price: Free

This tool checks the open and click rate of subject line keywords. You need to select a business sector and input the main keyword in your subject line. It will then provide you with the average open rate for that keyword, prompting you to change it if it is not high enough.

So never underestimate the importance of subject lines – they have the power to make or break your email marketing campaign. Get in touch with us to find out more about best practices to follow for all your Digital marketing endeavours.


Shobhit Patil
Co-Founder & CMO at Commversion UK Ltd.

Read Shobhit's articles and profile.