5 Free Tools to Test Your Subject Lines:

• TestSubject

• SubjectLine.com

• ISnotSPAM

• Hemingway App

• Email Subject Line Keyword Checker

We expect our subject lines to work for us in many different ways. They need to help you stand out in a crowded inbox, hook your reader, deliver on a promise, and ultimately get your reader to open and click-through an email.

If writing eye-catching and informative, yet restrained and brief copy is not your forte, join the group. A lot of marketing and sales professionals have problems writing effective subject lines, which is why free subject line testing/rating tools have been created.

Here are 5 free tools you can use to optimize your subject lines, improve your emails open, and generate higher click-through rates.

1. TestSubject

When you are creating copy for an email and want to see what it will look like on your users mobile device, you will want to check out TestSubject by Zurb. TestSubject's simple interface lets you see what your sender name, preview text, and subject line will look like on popular smartphones and mobile devices. Now you will know where your subject line, sender name and preview text are truncated on an iPhone 6 without going around the office looking for one to receive your test email. 

2. SubjectLine.com

SubjectLine.com is not only free, it is simple to use and understand. Simply type your subject line and hit enter. Then your subject line will be graded on a 0-100 scale, 100 being the best possible score. Once you receive your score, you will also receive an explanation of your score (-2 points for 4 or fewer words) and pointers on how to improve your copy.

3. ISnotSPAM

No one likes receiving SPAM, but what is even worse is having your message labeled as SPAM by an email client. ISnotSPAM is a tool you can use to assure that your email is not labeled as SPAM, which will not only help your emails find the right folder, but it will keep your email client happy with you. If your email sends are labeled as SPAM too many times, open rates will be the least of your problems. You can read more about SPAM and email re-engagement best practices here, "6 Steps to Email Re-engagement: A Quick Guide."

4. Hemingway App

Sometimes you need to be bold and straightforward, which may be difficult for some. If you find yourself typing around the bush, look into the Hemingway App. This app offers tips and content substitutions to help your subject lines and email body pack more of a punch. The app will develop a readability score for your copy and point out where improvements can be made.

5. Email Subject Line Keyword Checker

As the tool's name suggests, Email Subject Line Keyword Checker measures your keyword's impact on email open rates and click rates. This tool will help you refine your subject line and develop a message that is impactful and contains a keyword that your audience is already interested in.

Subject lines are the most important part of your emails. It is not enough for a subject line to grab the attention of your audience, they also need to deliver engagement results to prove that your emails are getting in front of the right people at the right time. These 5 free subject line tools are proven to help improve email marketing opens, click-through, and engagements from both active and inactive contacts.