You are currently viewing 15 Best Free Email Subject Line Testing Tools in 2024

The subject line is the critical element of running a successful email campaign. It is a first impression that people see before opening an email. Subject line is like a front door to your email, inviting people to step inside and explore what you have to offer. We have listed free email subject line testing tools that will help you to get a higher open rate and campaign performance.

Do you know 64% of people decide to open an email based on the subject line? And some people ignore and delete emails due to poor subject lines. Writing compelling subject lines is a crucial part of email marketing.

That’s why testing email subject lines is crucial for enhancing your email marketing campaigns’ open rate and effectiveness. Email subject line testing tools play a vital role in achieving your marketing goal. While there are numerous tools available in the market, it’s important to note that not all of them are free. Some tools require purchasing their email marketing platform in order to access their subject line testing features. This article has compiled a list of free email subject line testing tools that can help you maximize your open rates.


Why should you use email subject line testing tools?

To assess the efficiency and effectiveness of your email subject lines. Testing your subject lines is critical in order to gauge their impact and make informed decisions regarding email optimization. By using subject line testing tools, you can gather valuable data and insights that will help you craft compelling subject lines and enhance the overall success of your email campaigns.

What all things email subject line testing tool checks?

Here are some common elements that these tools typically assess:

  • Spam Filter Testing

Usually, the subject line testing tool checks spam trigger words in your subject line. Help you avoid getting flagged as spam and improve deliverability.

  • Character and Length Analysis

The tool examines the length of your subject line and analyzes the impact of different character counts to determine the optimal length for maximum engagement.

  • Emotional Impact

It also evaluates the emotional appeal of your subject line by analyzing the presence of certain words or phrases that elicit specific emotions, such as curiosity, urgency, or excitement.

  • Preview Text Optimization

Some tools even check the preview text that accompanies your subject line. They provide insights on how the preview text appears across different email clients and devices, helping you craft compelling snippets that encourage recipients to open your emails.

By checking these aspects, email subject line testing tools help you optimize your subject lines to increase open rates, engagement, and overall effectiveness in reaching your email marketing goals.


Top 15 free subject line testing tools

Let’s dive into free subject line testing tools that can maximize your open rate and the result of your campaign.

#1. Send Check It


SendCheckit is a completely free email subject line testing tool that can significantly improve your campaign results by optimizing your subject lines. This tool offers a comprehensive analysis, including scannability, reading grade level, length, preview, sentiment, “re:” or “fwd” usage, spammy words, bad tab words, exclamation marks, all caps words, excessive punctuation, and emojis. It then provides you with a score that indicates the effectiveness of your subject line.

If your subject line scores 90 or above, you can be confident that your email campaign will enjoy a better open rate. Personally, I’ve used SendCheckit free subject line checking tool for my own email campaigns, and it helped me produce a great result by improving campaign engagement and response rate.

Price: Absolute Free

Features: Effective and accurate testing tool


#2. Refine by Moosend

Refine by Moosend

Moosend stands out as one of the leading email marketing software providers, offering a comprehensive suite of tools to run successful email campaigns at a minimal cost. Among its offerings, Moosend’s Refine has gained popularity as a free email subject line testing tool.

Refine, a simple and user-friendly platform, allows you to access its subject line testing features without any subscription. Upon analyzing your subject line, it provides an open rate score based on industry averages and offers valuable suggestions to optimize your email subject line for improved results.

The best part? Refine is completely free to use. So, take advantage of this powerful tool without any cost involved. Give it a try and see your email marketing thrive!

Price: Just use it for a Free

Features: Top email marketing platform


#3. OmniSend – Email Subject Line Tester

OmniSend - Email Subject Line Tester

OmniSend is the ideal marketing automation platform for eCommerce OmniSend is known for its ability to drive sales effortlessly in the eCommerce space. It recently come up with an email subject line testing tool to improve your email marketing efforts.

Use OmniSend’s free email subject line tester to enhance your email open rates. Prior to sending your next campaign, you can analyze and improve your subject lines with ease. OmniSend subject line tool checks for Length, Wording, Scannability, and Subject line preview, and then provides a score based on these critical elements.

Looking to generate personalized and high-converting email subject lines? OmniSend also offers a Free AI subject line generator that can help you achieve just that. Elevate your email subject line with these powerful and user-friendly tools.

Price: Free

Features: Perfect E-commerce Marketing Platform


#4. Mailmeteor – Email Subject Line Tester


Mailmeteor is a reliable and free email subject line testing tool that you can count on. Its subject line tool thoroughly analyzes your subject lines and provides a score based on various essential elements. Additionally, the tool offers alternative subject line suggestions to help boost your open rate. Best of all, you can try it out completely free of charge. Give it a shot and increase your email marketing campaign performance.

Price: Free

Features: #1 Email marketing platform for Gmail


#5. CoSchedule


CoSchedule is another free email subject line checking tool you can consider. With CoSchedule, you can craft clickable subject lines that drive higher open rates, more clicks, and engaging conversations. The tool provides a score for each subject line, and a higher score indicates a perfect subject line that can significantly boost your open rate.

Take advantage of the CoSchedule to optimize your email subject lines and achieve greater success with your email marketing efforts.

Price: Free

Features: Best headline analyzer tool



As the name suggests, is the popular free subject line testing tool. You can use to test your subject line for better open rate and deliverability. It’s a good go tool for enhancing the effectiveness of your email marketing campaigns.

Price: Free

Features: Simple and effective tool


#7. Email Subject Line Grader by Net Atlantic

Net Atlantic

Email Subject Line Grader is a basic subject line tester that gives an overall rating of your subject line. It checks factors such as word count and word balance to help you optimize your subject lines effectively. It’s a simple subject line tool to enhance the impact of your email subject lines.

Price: Free

Features: A rapid and precise testing tool


#8. Automizy’s – Free Email Subject Line Tester


Automizy provides an email subject line testing tool that optimizes your subject lines. Using AI-powered technology, the tool grades your subject lines based on data from over 1 million campaigns. By leveraging this powerful tool, you can significantly increase the open rates of your email campaigns.

Price: Free

Features: Known for email marketing automation


#9. Mailshake – Email Copy Analyzer


Mailshake provides a comprehensive email copy analyzer tool that assesses subject lines and email content in real-time. Its goal is to enhance engagement, improve deliverability, and ensure the readability of your emails. However, honestly speaking, it may not be as effective as some other email subject line testing tools available in the market.

While it offers valuable features, you may want to explore alternative options for more robust subject-line testing capabilities.

Price: Free

Features: Best sales engagement software


#10. IsItWP


The IsItWP Email Subject Analyzer tool is your solution for writing subject lines that boost email open rates and improve your campaign’s ROI. This highly effective tool is completely free and allows you to test and optimize your email subject lines effortlessly.

Price: Free

Features: Simple and easy-to-use tool


#11. Attrock – Email Subject Line Analyzer


Attrock’s Email Subject Line Analyzer is a powerful tool designed to elevate your email marketing game. With Attrock, you can analyze and fine-tune your subject lines for optimal engagement and increased open rates. This user-friendly tool provides valuable insights and suggestions to help you craft compelling subject lines that captivate your audience.

Price: Free

Features: Best digital marketing company


#12. MailNinja – Free email subject line checker

MailNinja’s Free email subject line checker is an invaluable resource for anyone looking to optimize their email campaigns. With this tool, you can analyze your subject lines to ensure they are attention-grabbing, relevant, and enticing. By leveraging MailNinja’s expertise, you can significantly improve your open rates and overall email marketing success. Take advantage of this user-friendly and free tool to unlock the full potential of your email subject lines and connect with your audience like never before.

Price: Free

Features: An in-depth subject line tester


#13. GlockApps


GlockApps is a complete solution for email deliverability. It checks various elements like subject lines, email body, sender IP, domain, spam words, and more to optimize your email’s reach. With features like blacklist monitoring, preview tests across email clients and devices, and inbox placement monitoring, GlockApps ensures your emails land in the right place.

GlockApps offers 3 free spam tests, making it an excellent choice for email marketers seeking to run effective campaigns and accelerate business growth.

Price: Free & Paid

Features: Outstanding email deliverability platform


#14. Capitalize My Title

Capitalize My Title is another free email testing tool you can use for testing subject lines. It uses more than 60 data points to assess your email subject, grading it on a scale from 1 to 100 based on word usage, sentiment, and other critical factors that enhance open rates.

To get started just enter your subject line and click the “Analyze” button, and you’ll gain valuable insights to optimize your subject lines for maximum impact.

Price: Free

Features: Simple and light-weight platform


#15. First Page NZ – Free Email Subject Line Tester Tool

Catchy email subject lines are essential for getting clicks. Enhance your next campaign using First Page NZ’s fantastic free subject line tester software. Boost engagement, increase open rates, and leave a lasting impact on your audience.

Price: Free

Features: Intuitive subject line tester


Final Thoughts

Writing engaging email subject lines is an important part of an email marketing campaign. The right subject lines can grab attention, increase open rates, and ultimately lead to more clicks and conversions. Utilizing email subject line testing tools can significantly enhance your ability to create impactful subject lines and optimize your overall email marketing strategy.

With a wide range of subject line testing tools available, each offering unique features and capabilities, you have the opportunity to explore and find the ones that best suit your needs. From AI-powered analyzers to comprehensive email deliverability solutions, these tools empower you to make data-driven decisions and fine-tune your subject lines for maximum engagement.


Subject Line Tester Tools FAQs

1. How do you test a subject line?

Try out the free email subject line tool to assess how effective and efficient your subject lines are. It’s an easy and straightforward way to optimize your email marketing campaigns.

2. What is the best subject line tester?

We recommend using the best subject lines testing tools like SendCheckit, Refine, Omnisend, and GlockApps for better email performance and deliverability.

3. How long should a subject line be?

Shorter is better for most recipients, especially on mobile devices. Try to write the subject line within 9 words and 60 characters.

4. What subject lines end up in spam?

You should not use spam-triggering subject lines that include excessive capitals, misleading content, too much punctuation, spam words (e.g., “free,” “win”), non-compliance with regulations, resembling known spam, unusual characters, irrelevant content, and phishing attempts. Avoid these to reach the inbox.