Email Subject Line Generators
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15 Best Email Subject Line Generators to Boost Your Open Rates in 2024

An email subject line is the first thing an email recipient sees when they open their email inbox. Unfortunately, if the subject line is not captivating enough with the right words, there’s a high chance they will ignore your email.

In fact, according to a study, 33% of email recipients open emails based on the subject line alone. This is one of the key reasons why the email subject line for your email campaign needs to be striking and catchy.

An excellent way to get around that is by using subject line generators. However, with many free email subject line generators available online, it can be slightly tricky to find the right one to get your desired business results.

In this article, we have identified a detailed list of the best 15 free email subject line generators that you can use to create subject lines with high open rates.

Table of Contents

  • What Are Email Subject Line Generators?
  • Are Cold Email Subject Line Generators Useful?
  • What is a Good Subject Line?
  • How Long Should the Subject Line of an Email Be?
  • What Types of Email Subject Lines are Prohibited by the CAN-SPAM Act?
  • 15 Best Free Email Subject Line Generators To Use in 2024
  • Email Subject Line Tester Tools
  • How To Improve Email Subject Lines?

What Are Email Subject Line Generators?

An email subject line generator is an AI tool that helps email marketers and salespeople create relevant subject lines for your email campaigns.

Since email subject lines are essential to the success of email campaigns, email subject generators help create intriguing subject lines that you can use and work around to create a killer subject line for your campaign.

Now that you know the basics, let’s dive into the best part of this article – email subject line generators and other essential tips about subject lines.

Are Cold Email Subject Line Generators Useful?

Are email subject line generators effective? Can you trust them to create catchy email subject lines for your campaign? Yes, they are!

Subject line generators are super effective in creating working email subject lines that can significantly increase sales and improve customer relationships. They are AI-powered tools that generate subject lines that increase your email open rates based on your suggestions.

Though you might want to tweak this a bit to fit your needs, you can always trust email subject line generators to get the job done. However, remember that this does not undermine the intellectual ability of marketers to create impressive and catchy subject lines.

Email subject line generators are helpful when you need to create tested and proven email subjects easily and quickly and, most importantly, when you need email subject lines on a large scale.

What is a Good Subject Line?

A successful email starts with a subject line that is short, crisp, and straight to the point in a way that quickly catches the attention of the email recipient while also informing them what the email is all about.

Good subject lines should be personal and descriptive and urge people to check out your email content. Keep in mind your email’s subject line is as important as your email body; hence make sure that it’s crisp, informational, and catchy for your recipients.

How Long Should the Subject Line of an Email Be?

Email subject lines are relative; the length of the subject line depends on many factors. It would be best if you considered that email readers could see up to 60 characters on the desktop, whereas mobile users can only read 20 – 25 characters on their mobile phones.

According to a study by Marketo, the average email subject line length for your campaign is between 41 characters and seven words. Other research studies suggest that your email subject line should not be more than nine words and 60 characters to make it responsive and functional on all screens. The safer number to go for is below 40 characters.

Whichever word count you opt for, ensure that the email is short and straight to the point.

What Types of Email Subject Lines are Prohibited by the CAN-SPAM Act?

The CAN-SPAM Act is a law that sets rules for commercial email, establishes requirements for commercial messages, gives email recipients the right to stop spam messages from coming, and rules out tough penalties for violations.

If you are going to write effective email subject lines that drive sales, you must understand what’s right and wrong to save you time and headaches down the line.

According to the rules of the Act:

  1. Avoid clickbait content in your subject lines – This means that the subject line must accurately reflect the content of the message and not beat around the bush to get them to open the email. Beyond just the law, staying off deceptive subject lines can also help to build a positive relationship with your prospects.
  2. Avoid using question marks and exclamatory marks in the same subject line – Using this combination can get your email flagged as spam before your email recipient even has a chance to open and read the email.

15 Best Free Email Subject Line Generators To Use in 2024

Here are the 15 best free email subject line generators that you can use to generate subject line ideas that drive sales and enhance your customer relationships.

1. Jasper

Jasper subject line generator

Jasper is an Artificial intelligence (AI) based content and copywriting tool that creates high-quality search-engine-optimized content for different uses. In addition, it has multiple templates to create original, highly engaging email subject lines.

To generate the email lines, you are required to enter your company or product’s name, tone of voice, and a short description of what the email is about to generate a list of powerful email subject lines that you can use or tweak slightly to suit your needs.

2. SalesBlink


The sales automation tool, SalesBlink, has a free email subject line generator. With two simple steps, you can quickly generate personalized and catchy email subject lines using the device. They are by,

  1. Entering the service you provide
  2. And the name of the recipient company

SalesBlink provides you with five catchy subject lines that your can use for free in your email campaign. Importantly, this tool is also user-friendly and easy to use.

3.‘s email subject line generator enables users to generate subject lines for emails on the go by choosing an option from the available categories and entering a keyword to create subject line options that best fit their needs. The results are reportedly more appropriate for B2B email marketing campaigns.

4. Active Campaign

Active Campaign

ActiveCampaign CRM is a tool that you can use to search for meaningful subject lines that improve your email open rates.

It’s a free subject line generator that can help you create email titles using keywords. Its three main categories to choose from include:

  1. Pain Points
  2. Benefits
  3. Topics

5. Portent


Portent is one of the most straightforward email subject line generators that can help you create subject lines by just including the topic of your key message or products or solutions.

Though it is not intended for creating email subject lines, the subject line suggestions can be used as inspiration. You only need to click “See another title” to get a new title. While it might be a bit ambiguous, you will only be able to figure out the appropriate term category to use.

6. Automizy


Automizy is an email marketing automation software with an AI-powered email subject line tester, generator, AB testing, and email automation. Its free subject line generator enables you to create tailor-made subject lines for your email.

Keep in mind that it works slightly differently from others as it enables users to copy and paste the email’s body on the tool to generate the best subject lines for the email.

7. Keap


Keap is an easy-to-use CRM platform with many great tools that can help you organize leads and automate repetitive tasks and in-app payments.

Its free email subject line generator can help you create subject lines that capture your recipients’ attention using various email formats. It provides subject line ideas for sales and marketing emails.

To use this tool, you need to select the type of email you want to send from the following email options:

  1. Newsletters
  2. Re-engagement
  3. Follow-up.
  4. Promotion.
  5. Resources.
  6. Registration.

After you indicate the target audience, interest category, and desired outcomes to get five personalized email subject lines

8. Headline And Subject Line Generator By Google

Subject Line Generator By Google

This tool by Google is an extension you can add to chrome with over 500 combinations of headlines and subject lines to use while on the browser.

It helps users create effective headlines and email subject lines important to their email goals. By just entering a target keyword, you get suggestions of catchy subject lines that you can use.

You can choose from four categories – List, How To, Question, and General. After selecting the category of interest, you enter your keyword or keyphrase.

9. Kickass Headline Generator

Kickass Headline Generator

Kickass headline generator is a free high-converting headline generator for Sumo, a cloud-based email capture tool that helps to improve website traffic and enhance the subscriber list using email opt-in forms. It enables users to write engaging headlines, titles, and perfect email subject lines.

Unlike other tools that give you headline suggestions, this requires setting some conditions in the device to get formulas. After this, you select your headline or subject line format and add elements.


Emaildrips is an email marketing tool that helps to quickly generate high-converting email sequences and sales funnel for clients using proven templates, examples, and courses.

It has a subject line generator compatible with companies across all industries. In addition, it is a free tool and does not require that you share your email address to use it.

An exciting feature of this tool is that it doesn’t limit the number of times you can create. You can also customize the subject lines easily by entering the details asked in the subject line generator.

11. Copymatic


Copymatic is a powerful AI-powered copywriter and content writer who helps users write digital ads, website copy, or blog content in seconds.

It has a free, user-friendly subject line generator that can help you create marketing emails by just filling out the form to tell the AI what you want to write about or the email subject.

Enter the tone of your message, the name and description of your product, and change how creative you want the AI assistant to be. They also provide ten free credits to check out the complete generator.

 12. Encharge


Encharge is a free AI-powered email subject line using the GPT-3 technology. Using the protocol created by OpenAI helps users create human-like word combinations and write good email subject lines.

By filling in your company name, the Subject of your email, and chosen tone in the appropriate fields, you can click create to get about seven good email subject line suggestions. In addition, it provides various email tone options, from appreciative to urgent.

13. INK


INK is an AI-powered catchy email subject line generator that can help you create your own email subject lines. In addition, it aids in creating brief subjects that instantly center on the user.

It can be functional and helpful in creating original and eye-catching cold email subject lines by filling out the box with your business name and a brief concept. Once you have a list of email subject lines, you click the “Create” button to create it. Aside from making the subject line suggestions, it also ensures that:

  • The subject lines are distinctive, pertinent, and devoid of spam terms.
  • Keeping the email subject line length to 40 characters.
  • Increasing an email’s open rate while keeping the subject line interesting.

14. is an email subject line generator that will provide you with content marketing ideas based on the topic of the email, a description of your business, and by choosing “Inspire me” to use their subject line generator.

It provides you with a suitable subject line based on your search query. This tool can be beneficial in creating subject lines that drive sales as it uses AI to make suggestions and has no usage limit.

15. Content Row

Content Row

Content Row is a full-featured content management solution with a subject line generator that doubles as a headline analyzer and a headline generator. It is a simple and free tool that lets you do three headline searches daily.

A downside of this tool is its restricted use which only allows three headline searches for free users. PRO subscribers get unlimited usage.

Email Subject Line Tester Tools

There are many processes involved in creating subject lines for your email campaigns.

Aside from creating attention-grabbing subject lines, you also need to test the subject lines to ensure that you try the Subject for all possible span filters, misleading information, and any information that can get in the success of your email campaign.

You need to gather a lot of data based on your past email campaigns and understand what works for your target audience and industry. To achieve this task, you can check out five email subject line tester tools.

1. Test Subject

Email Subject Line Tester Tools

Test Subject is a free subject line tester by Zurb. It shows how your sender name, subject line, and pre-header text will appear on mobile devices. It gives an instant preview of how the email copy will appear to your audience.

2. Spam Check

Test Subject

As you can already guess from the title, this free email tester tool by Postmark analyzes your subject line, pre-header text, email message, and sign-off for spam-triggering words and gives you the report.

3. Email Subject Line Grader

Spam Check

This free subject line tester by Net Atlantic gives an overall numerical score on how compelling your subject line is, along with suggestions for improving it.

It also shows how close your character and word count are to the ideal length. This tool tested the overall effectiveness of the email copy, word count, word mixture, balance, and type.

4. ISnotSPAM

Email Subject Line Grader

This free email tester tool flags words and phrases in your subject line and email body that can trigger spam filters.

Please send your email to the address provided on their homepage and receive a comprehensive spam report in return. It also checks that your ID is clean and suggests solutions for spam-related issues that will most likely arise.

5. Headline Analyzer


This free tool by CoSchedule was initially built to analyze blog and article headlines but works perfectly for subject lines.

It gives you an overall headline score and provides structure, grammar, and word placement tips. In addition, it tests overall copy effectiveness, word balance, length analysis, keywords, type, and sentiment.

How To Improve Email Subject Lines?

Email subject lines can make or break your email campaign. It’s the first thing your prospects notice and decide whether to take the lead, read your email, or ignore it and move on. The following tips can help persuade your prospects to open and read through your email.

  1. Shorten your email subject line.
  2. Avoid spam words in your email subject lines.
  3. Include a deadline in the subject line (but ensure that it is truthful and not deceitful).
  4. Give direct instructions in your subject line.
  5. Try using a teaser in the subject line to get people to open your email.
  6. Ask open-ended questions in the subject line.
  7. Share new and exciting news or announcement in the subject line.
  8. Personalize your email subject lines by adding the prospect’s name, company name, etc.,
  9. Say something unexpected or intriguing in the subject line.
  10. Highlight video and other multimedia in your email subject line.

Email Subject Line Generators: The Conclusion

Email subject line generators are super helpful tools that can offer the right ideas and suggestions for your email subject lines that drive higher open rates.

Along with the subject line generators, the subject line testers are also handy tools for improving the quality of your email subject line and increasing your open rates. Most devices are mobile-friendly, with an ideal word count that concentrates on passing spam filters, while most are free.

Although email subject line generators are excellent and effective for creating subject lines fast without stress, the suggestions are primarily based on algorithms. So while they might be good, you might not find the uniqueness and personalization in the email lines.

Hence, you must work around the subject lines to add a human touch and check your email copy’s spelling, grammar, SEO, and relevance.


1. Are subject lines generator useful?

Email subject lines are helpful tools that help you create catchy and effective subject lines that can help you quickly and easily increase your open email rate quickly and easily.

2. How can you improve email subject lines?

Email subject lines are the first thing your email recipient sees in their inbox before deciding whether they want to open the email. To improve your subject line, consider adding symbols, emojis, or numbers that are important to boost your email open rate.

3. How personalization in the subject line helps?

Personalization works wonders with emails. Personalizing your email subject line can significantly impact the success of your email campaigns as it helps your recipients feel more important when they see their name in the subject line. Aside from triggering the feeling of importance, it also compels them to open the email.

4. How long should the subject line of the email be?

A desktop email client can see up to 60 characters in the email, whereas mobile email clients can see approximately 20 – 25 characters. A best practice for email subject line length is to keep the subject line less than 50 characters and 6-8 words to make it suitable for all screens.

5. What not to include in your email subject line?

Avoid using filler words like “Hi,” “Hello,” and “Nice to meet you.” Also, avoid using false, dramatic, and controversial statements in the email subject line. While this can get them to open the email, they might get disappointed if your email copy doesn’t stay true to the claims or statements.

Lastly, avoid using charity-like words like “donate,” “fundraiser,” and “raffle” in the subject line, even if you’re a charity organization. Instead, use words like “help” and “helping” to convey the message.