Email Marketing

9 Best email subject line generators: a smarter way to increase your open rates

9 Best email subject line generators: a smarter way to increase your open rates

Writing a good subject line is a fine art that could mean the difference between your email being opened or ignored. In fact, some of the most impactful split tests we run at AWeber are subject line tests. Why? Because the more people that open your email, equals more people reading your content which eventually equals more clicks.

It can be tough to write a subject line that captures enough attention to get someone to open, especially when you first start building an audience. Heck, even seasoned email marketers struggle creating the perfect subject lines.

As a result, lots of subject line generators have been built to try and make this easier. But they’re not all built the same.

I tried some of the most popular subject line generators so you don’t have to! In this post, I’ll tell you how much they cost (some are free), how good the subject lines are, and which subject line generator might be right for you.

The best email subject line generators


Image of AWeber's AI subject line generator

Writing subject lines has never been easier (or more effective). With AWeber’s AI subject line generator you can make sure your subject lines meet best practices for deliverability and impact.

Plus with AI functionality now built in, you can overcome that ol’ creative block and let the subject line generator provide you with compelling subject lines, each based on the content of your email.

But you get way more than just a subject line generator, you’ll get an email marketing and automation platform, a way to grow your email list with landing page builder and sign up forms. Plus you can use the AI writing assistant to craft your entire email message.

AWeber's email marketing builder with AI writing assistant


Free plan which includes unlimited subject line suggestions.

Paid plans start at $30/month.

What we ask for to generate your subject lines:

Nothing. Our AI subject line generator does all the work for you. It will provide you suggestions based on your email content. Just write your email, then select generate ideas.

You can customize your results by choosing from friendly, professional, urgent, or inspirational tone. And by email style where your options include informational, newsletter, blog, promotional, education, information.


You don’t have to worry about providing the perfect instructions to get a subject line that aligns with your email copy. The benefit of AWeber’s AI subject line generator is that it provides you perfectly matched subject lines with your email and it follows email marketing best practices. The most difficult part of this subject line generator is trying to pick which one to use.

Favorite subject line generated: 🍋 What do lemons have to do with testing?

Score: 5/5 (sure I’m a little biased, but using the power of AI, the results are truly amazing)


Copy.ai's subject line generator platform

Copy.ai is a tool that uses artificial intelligence (AI) to write marketing resources for you. They offer everything from email subject lines and ad copy to fully written blog posts. Their interface is clean, helpful, and easy to use.

It’s worth noting that since email marketing isn’t Copy.ai’s bread and butter, the results you get are not optimized or tested in any way for the inbox. 


Free plan includes 2,000 words per month.

Paid plans start at $49/month for unlimited words and additional pro features.

What they ask for to generate your subject lines:

  • What is the goal of your email?
  • Tone, with options: friendly, luxury, relaxed, professional, bold, persuasive, witty, empathetic, adventurous, or write in your own.


Copy.ai’s results were okay, if fairly generic. Many of them felt like blog post titles rather than subject lines, with a number at the beginning (e.g. 7 Things You Didn’t Know About Cooking). The subject lines weren’t optimized for any audience, either. But, you may find their results helpful as a starting point to create your own subject lines (especially since Copy.ai is free).

Favorite subject line generated: Air fryer recipes for lazy nights (and busy ones, too)

Score: 4/5 


Anyword's subject line creator tool

Anyword is an AI-generated copy tool built specifically for “performance marketers.” You can use it to create ad copy, blogs, and emails as well as product descriptions and SMS messages. 

Anyword’s email subject line generator creates as many results as you need, and it gives each a score. Click on more details for the score and it tells you which age and gender this subject line is likely to appeal to most.


7-day free trial includes their starter plan and 2,500 word credits.

Paid plans start at $49/month for 100+ prompts.

What they ask for to generate your subject lines:

  • The full text of your email.
  • Your target audience.
  • Talking points.
  • Tone of voice: engaging, conversational, hard sell, playful, 5th grader, confident, or write in your own.


Anyword’s results were fairly repetitive and generic. When I gave it a prompt for “summer pork recipes,” all three results had the word “sizzling” in them. I liked that the subject lines were fairly short, which felt different than a blog title. They mostly included action words, but didn’t seem like they’d stand out in an inbox. 

Anyword also gave me a few subject lines with bad scores (as low as 28 out of 100). If they have scores, I think they should provide you with only the best subject lines.

Favorite subject line generated: Sizzlin’ Summer Swine Recipes

Score: 4/5


Scalenut's AI-generated subject line creator platform

Scalenut was my favorite tool to use. It was easy to sign up and find the email subject line generator. Plus, Scalenut includes a document editor — a place where you can copy and paste any or all of the generated subject lines, the full email text, and anything else that helps you decide on the right subject line.

Scalenut uses AI to generate marketing copy and also includes an SEO tool that you can use to create guidelines for your blog posts.


7-day free trial.

Paid plans start at $39/month for 100,000 words per month.

What they ask for to generate your subject lines:

  • Brand name
  • Brand description
  • What is the email about?


Scalenut had my favorite results. There was a lot of variety in the tone, length, and context of the subject lines they created. And I felt like they “got it” when it comes to actually writing a subject line — they didn’t just sound like a bunch of blog post titles.

Plus, Scalenut included some emojis in their subject line results.

Favorite subject line generated: Air fryer recipes? Yes please!

Score: 5/5


Subject line creator tool from Encharge

Encharge has a free email subject line generator using Chat GPT-3 technology. It’s quick and easy to use — you don’t need to create an account or sign in. The purpose of Encharge’s email subject line generator is to do just that — generate subject lines. It doesn’t offer any other AI copy options.



What they ask for to generate your subject lines:

  • What is the email about?
  • Company
  • Tone: appreciative, assertive, awestruck, candid, casual, cautionary, compassionate, convincing, earnest, enthusiastic, formal, friendly, funny, humble, humorous, informative, inspirational, joyful, passionate, thoughtful, urgent.


There was a lot of variety in the results I got from Encharge, and they were all definitely geared towards a subject line, not blog posts. And, it’s worth noting that Encharge was the only subject line generator to include a price in the subject line for my product sales email ($19.99 for a cookbook).

Favorite subject line generated: Cooking for One or Two? Increase your cooking skills with this new online course!

Runner up: Porktastic, Eh?

Score: 3/5


Inforall AI-powered email subject line generator platform

Inkforall is a fairly simple AI writing tool that creates many different kinds of content, including email subject lines. It will create three email subject lines for you from your prompt, and you can easily click to save one or all of them. Inkforall’s interface is easy to navigate and nice and simple to use.

In addition to copy, Inkforall can also generate images for you. Plus, their tool can generate copy in 20+ languages.


5-day free trial includes 10,000 words.

Paid plans start at $49/month billed annually for unlimited AI writing.

What they ask for to generate your subject lines:

  • Product name
  • Product description
  • Tone: adventurous, board note, bold, comedian, empathetic, friendly, funny, gloomy, investor note, Joe Rogan, luxury, Obama, persuasive, professional, relaxed, Shakespeare, Warren Buffet, witty.


With tone options for Obama, Shakespeare, and Warren Buffet, the results can vary a lot more — which provides a lot of different types of subject lines. There was not a lot of variation within any given tone, however. These results are a great jumping off point to make modifications or for someone who doesn’t want too many options to choose from.

Favorite subject line generated: Cooking is too intimidating. Let’s fix that.

Score: 3/5


Copymatic's email marketing subject line creator platform

Copymatic is an AI-powered platform that produces content from blog posts to landing pages to subject lines. It can create up to 8 subject lines in one request. You can save or copy any of your content. The interface is really clean and easy to use.


Free trial which includes 1,500 credits (each credit is equal to one word)

Paid plans start at $29/month billed annually for unlimited words.

What they ask for to generate your subject lines:

  • Level of creativity. The higher the creativity level, the less repetitive results you’ll receive
  • Product name
  • Product description
  • Your audience
  • Tone: professional, childish, luxurious, friendly, confident, exciting


I had eight subject lines created and felt 7 out of 8 sounded clever and original. However a few of the subject lines were long, I fear a good portion of the copy would be cut off in the recipient’s inbox. However, you could use those as inspiration and reduce the length to come up with a creative subject line.

Favorite subject line generated: These summertime pork recipes for the grill will make your mouth water

Score: 4/5 


StoryLab.ai email subject line generator platform

StoryLab.ai‘s bread and butter is generating shorter form AI content from titles, email copy, content ideas, social descriptions, and subject lines. 


Free – 3 AI generated runs/month

Paid plans start at $19/month for unlimited AI runs

What they ask for to generate your subject lines:

  • Topic you’d like to cover
  • Details StoryLab.ai should know about your company, email details, customer pain point
  • Writing style: Professional, witty, list, storytelling, bold, adventurous, friendly, persuasive, empathetic, sassy, classy, casual, comedic

Results: StoryLab.ai provides five results. The subject lines generated were good, but not very original. And all the subject lines were very similar. I would have liked more variety to choose from. Overall not a bad option but I found better subject line generators.

Favorite subject line generated: Summer Grilling: 5 Must-Try Recipes

Score: 3/5

Subject line generators to skip

We tried a few subject line generators that just didn’t produce results that were super helpful. We suggest skipping over the Google Chrome subject line generator plugin, ActiveCampaign’s subject line generator, and Keap’s subject line generator.

Best subject line graders

Once you’ve chosen your subject line generator and gotten a list of subject lines, you may want to run each of them through a grader to gauge how effective they are likely to be (and help you choose which to use).

Here is a list of five free subject line graders:

  1. CoSchedule Headline Analyzer
  2. Advanced Marketing Institute’s Headline Analyzer
  3. The Email Subject Line Tester by Litmus
  4. Mizy
  5. SubjectLine.com

Did the subject line generators help you get better results from your emails?

Did you save time? Get better open rates? Tell us in the comments which subject line generator you decided on and how it helped you.

The post 9 Best email subject line generators: a smarter way to increase your open rates appeared first on AWeber.

July 10, 2024 Original Source https://blog.aweber.com/learn/best-email-subject-line-generators.htm

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