• 7 Free Subject Line Tools to Boost Your Email Opens

Free Tools for Email Subject Lines

Research has long proved that your subject lines can be the difference between your emails being opened, immediately trashed, or sent straight to the spam folder. Here are 7 free tools that can help you come up with subject lines that facilitate email marketing success.


Free Tools for Email Subject Lines

Tools to Help You Improve Your Email Subject Lines

1. Subject Line

This tool is about as simple and straightforward as it gets. You enter your subject line and you’ll be shown a list of the good and bad components it contains. Each good and bad element of your subject line is assigned a point value so you add or lose points based on quality, and receive a score out of 100. For instance, you might lose 15 points for lacking a sense of urgency or gain three points for using the second person POV.

What makes Subject Line so valuable is the fact that it’s based on research conducted on over 3 billion email messages (and counting). Those messages, subject lines included have been tested on over 800 different rules and factors so, as you can imagine, the creators of this tool know what works.

2. Headline Analyzer

This analyzer, provided by CoSchedule, provides more insight into the strength of your subject lines (and blog post titles). It takes into account the use of common, uncommon, emotional, and powerful words. Not to mention the type of headline, sentiment, keyword usage, length, and the placement of key ideas.

Headline Analyzer is especially useful if you want to compare the strength of several subject lines in one session. Entering a new option doesn’t erase your previous ones. Rather, the Headline History section allows you to see all scores at a glance and switch back and forth to consider the finer points.

3. Email Subject Line Tester

Also created by CoSchedule, Email Subject Line Tester is, of course, specifically for email subject lines. Like Headline Analyzer, it has the Headline History feature and shows previews of what your subject line will look like on various devices.

However, the rest of the analysis is a bit different. It reports on words that increase and decrease email opens, the case your subject line is written in, whether there are any number present, and length. Each section provides brief but valuable research-backed tips that can help you make improvements.

4. TestSubject

This tool from ZURB is focused solely on mobile. In addition to showing how your subject line will look on the most popular devices, it shows how your sender name and pre-header text look. This extra insight can help you tighten up your emails before you send them and find out that they’re not as effective as you’d expected.

Since TestSubject is all about the appearance of your subject line and not necessarily the content of your emails, it’s best to pair this tool with one that does analyze the content.

5. Send Check It

Send Check It provides one of the more detailed analyses out there. It assigns subject lines a letter grade and corresponding point value based on scannability, length, reading grade level, sentiment, personalization, and type. It also checks for:

  • Words often found in spam emails
  • Words that get your emails sent to tabs that are checked less often (e.g. Promotions)
  • Overuse of exclamation points or other punctuation
  • Potentially beneficial or risky capitalization

Last but not least, it shows you a desktop and mobile preview.

6. IsNotSpam

Created to alert senders if their emails trigger spam filters, IsNotSpam is an invaluable tool. All you have to do is send your email to the designated address and then view your report. Send Check It will point out words or phrases that could result in your message being marked as spam.

In addition to running checks on your subject line, you’ll get additional insights into your entire email message.

7. Capitalize My Title

This is a good tool to keep your subject lines consistent in terms of capitalization, especially if you use a particular style (e.g. AP, Chicago, etc.). If you’re in a hurry, the tool is fast and easy to use. But Capitalize My Title also provides helpful rules of thumb on capitalization so that, eventually, you won’t need the capitalization checker.

Start Testing Your Subject Lines

As you’ve seen, just about every aspect of your subject line can be tested from its appearance, to its content, to its format, and beyond. By doing your due diligence before you send a message to your subscribers, you boost your chances of getting the results you want. Why not try out the tools listed above for yourself, and see how you can combine them to write more powerful subject lines?


Looking for more help with email subject lines? We’ve got a free guide for you!

Nia Gyant
Nia Gyant
Nia Gyant is passionate about helping small business owners create and execute solid marketing strategies, and writes blogs with a particular focus on inbound marketing and branding.

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