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10 Best Email Subject Line Generators For 2024

Struggling to come up with interesting email subject lines for your next campaign? Use one of these email subject line generators to skyrocket your open rates.

Published on Jun 04, 2024

If you're struggling with your email marketing campaigns and experiencing poor email open rates—you need to focus more on your email subject lines.

As per Invesp's research, a whopping 69% of recipients report emails as spam solely based on the subject line, and 47% of recipients open emails looking at the subject lines. 

Thus, no matter how beautifully you craft your email's internal body and include CTAs—it won't be of any use unless your recipients bother to click on the email and open it. And an effective, attractive, and personalized subject line is the best way to grab the recipient's attention and push them to open and respond to your email.

However, creating fresh and creative copy for subject lines day after day can get cumbersome for most marketers. 

This is where the email subject line generators mentioned in this article help. We share the best free and paid email subject line generators you can try for your next email marketing campaign. 

First, let’s go over the essentials of writing effective subject lines.

Elements of a high open rate subject line

Personalization

Tailor subject lines to include the recipient's name or other relevant details. This added level of personalization can increase open rates, as it creates a sense of individual connection between the sender and receiver.

Urgency

Creating a sense of urgency in the subject line can encourage recipients to open the email right away. Using phrases such as "Limited Time Offer" or "Last Chance" can create a fear of missing out (FOMO) and entice readers to open the email.

Relevance

Subject lines should be relevant to the content of the email. If the subject line does not align with the email's message, recipients may feel misled and be less likely to open future emails. Make sure the subject line accurately reflects the content of the email.

Clarity

Keep it clear and concise, avoiding ambiguity or confusion. The subject line should give recipients a clear idea of what to expect in the email, making them more likely to open it.

Personalization

Tailoring subject lines based on the recipient's interests or behavior can make them feel like the email was specifically created for them. This personal touch can increase open rates and engagement with the content.

Emotion

Evoke emotion to connect with the reader on a personal level. Whether it's excitement, humor, or empathy, using emotion in the subject line can make it stand out and entice recipients to open the email.

Questions

Pose a question to engage recipients and encourage interaction. This can also make the email feel more conversational and less like a sales pitch, leading to a higher open rate. Make sure the question is relevant and thought-provoking.

Numbers

Use numbers to make the subject line more specific and impactful. For example, "10 Tips to Boost Your Productivity" can be more enticing than "Tips to Boost Your Productivity."

Emojis

Using emojis in email subject lines has been proven to increase open rates, especially when used in bookend format (the same emoji at the start and end of a subject line). However, use them sparingly and make sure they are relevant to the content of the email. Overusing emojis can come across as unprofessional or spammy.

Top 10 email subject line generators to get higher open rates

Considering the importance of subject lines for your email marketing efforts, thinking out of the box to write compelling subject lines can get exhausting, especially when you need the subject lines on a large scale.

You can speed up this process using an email subject line generator, choose from the outcomes, or even seek inspiration to write subject lines that seem more attractive to your target audience. 

Here are the ten best email subject line generators you can try that help generate eye-grabbing subject lines for your marketing needs. 

Want to generate entire emails? Try our Email Generator.

1. Jasper

Jasper email subject line generator

Jasper is an artificial intelligence (AI) based content and copywriting tool that generates search-optimized and original content from scratch. It offers multiple templates to create the perfect headline, product description, emails, landing pages, and email subject lines

By entering your company or product's name, tone of voice, and what your email is all about in Jasper's email templates—it generates a list of intriguing email subject lines you can use or tweak to suit your needs. 

You can play around and try a different tone of voice that entices subscribers to open your emails. For instance, a professional tone of voice will generate a more direct subject line, whereas a secretive tone will allow you to generate curiosity amongst your subscribers to see the email's content. 

The best part about Jasper is that it isn't just restricted to being an email subject line generator. Besides the subject line, its email marketing template helps generate a compelling email body and Call To Action (CTA) in less time if copywriting isn't your strongest suit. 

Pros 

  • Excellent customer support
  • Generates multiple relevant subject lines to A/B test them on your subscribers
  • Offers a five-day free trial
  • Offers one of the best Chrome extensions for email (and other content types)

Cons 

  • Doesn't offer a tablet or a mobile application

Pricing 

The Creator and Professional plans cost $39 per month and $59 per month, respectively. There are also flexible pricing plans for enterprise-level solutions.

Platform

Web-based 

2. Salesblink 

Salesblink free cold email subject line generator

SalesBlink offers a full-stack cold sales outreach solution for client outreach, prospecting, and lead generation. Its cold email subject line generator is specifically designed for sales emails.

All you need to do is enter the service you offer, like content writing, social media marketing, web designing, or graphic designing, and enter the recipient company name you want to pitch your services to, like Hubspot or GoDaddy. 

Once you click the 'Generate Subject Lines' button—SalesBlink generates five good email subject lines that can help attract the recipient's attention and close clients faster. 

Pros 

  • An excellent tool for agencies and freelancers that regularly do cold outreach
  • Gives as many subject lines as you want with the 'Generate More Subject Lines' button

Cons 

  • Needs bug fixing
  • The interface requires improvement

Pricing 

Free 

Platform

Web-based 

3. ActiveCampaign

ActiveCampaign email subhect line generator

ActiveCampaign provides a simple way to generate keyword-specific email subject lines. 

All you need to do is choose a particular keyword category—Benefit, Pain Point, and Topic, enter a keyword, like sales, money, or cart abandonment, and click on the 'Generate subject line' button. 

It generates four great subject line suggestions, and you can view more results by clicking on the ‘Generate more suggestions’ button below the listed subject lines. 

While it's quite easy to use, the problem with ActiveCampaign is that it doesn't ask for the tone of voice you need for your subject lines—making the suggestions blatant and repetitive. 

Pros 

  • Offers A/B testing to test different subject lines and choose one that performs the best
  • The paid plan offers great email marketing automation for broadcast, targeted, scheduled, and transactional emails 
  • Easy to use interface

Cons 

  • The suggestions get repetitive
  • Offers unresponsive customer support

Pricing 

Free 

Platform

Web-based 

4. Encharge

Encharge AI subject line generator

Encharge is the only free AI-based email subject line generator based on GTP-3 technology that strays away from those basic templated email subject line suggestions and delivers contextual, unique, and high-converting subject lines in human-like language. 

Enter some context about your email, your company name, and the tone, and Encharge generates seven amazing and creative subject lines you can use or seek inspiration from. 

Pros 

  • Offers over 20+ tone of voice options, including assertive, appreciative, informative, convincing, friendly, and urgent
  • Keeps generating more and more subject lines when you keep clicking on the 'Generate AI Subject Lines' button until you find an appropriate option
  • Easy to use and beginner-friendly

Cons 

  • The paid plan lacks many important integrations, like e-commerce and ClickFunnels, compared to other tools, like Jasper

Pricing 

Free 

Platform

Web-based 

5. Copy.ai

Copy.ai subject line templates

Copy.ai excels in generating short-form content, like social media captions, headlines, blog title ideas, and email subject lines. 

You must enter your brand or product name, product description, and tone of voice to generate a list of catchy email subject line ideas. It lets you choose from nine tone of voice options, including friendly, professional, witty, persuasive, and bold. 

In addition, you can also click on the 'Make More' button if you'd want to see more subject line results. 

One of the excellent perks of Copy.ai is that its product description comes with an abundant word limit of 1000—allowing you to enter as much detailed information as possible to let the tool generate relevant suggestions. Another great feature is to save all your favorite subject lines and refer to them on the 'Saved' tab. 

Pros 

  • Allows you to copy all the subject line results and paste them elsewhere—on a spreadsheet or Google Docs
  • Allows you to translate your copy into 25+ languages via the paid plan
  • Has a user-friendly messaging system and customer support

Cons 

  • The tool sometimes lags while generating content

Pricing 

Free 

Platform

Web-based 

6. Keap

Keap email subject line generator

Keap is a much more unique subject line generator tool compared to the others mentioned here—considering the fields it requires you to fill to generate relevant results. 

First, you must choose the 'type of message' or emails you need to send, such as a newsletter, follow-up, registration, promotion, re-engagement, or resources. Next, you need to enter the keyword or category of interest, the results your recipients want, and their biggest pain point. 

These necessary details allow Keap to generate subject lines that lead to more clicks, conversions, and sales—facilitating the success of your email marketing campaigns. 

Pros 

  • It lets you email the subject lines you generate with a single click with the 'Email results to me' button
  • User and mobile-friendly

Cons 

  • Poor customer support

Pricing 

Free 

Platform

Web-based 

7. Cold email subject line generator by Reply.io

Reply.io cold email subject line generator

Reply.io provides an advanced AI-based cold email subject line generator—best-suited for B2B email marketing campaigns. 

It requires you to choose a suitable Category—Benefit, Problem, Personalized, or COVID-19 and a relevant keyword that goes with the category you choose for your email subject line. 

For instance, if you choose the category 'Problem’, your keyword can be cart abandonments, bounce rates, or poor SEO performance. Once you add these details and click the 'Generate Subject Line' button, Copy.ai generates six subject line results optimized for clicks and open rates. 

The best feature of this email subject line generator is its AI-powered tool—email quality check. Once you choose a perfect email subject line, you can perform a quality check using this AI tool. It checks the quality based on factors like subject line length, word count, question count, positivity, and reading level. 

Pros 

  • Helps generate actionable subject lines that maximize reply rates
  • The email quality check tool offers accurate improvement suggestions 

Cons 

  • Comes with a 14-day free trial

Pricing 

Free for 14 days. The Email Search plan comes with two pricing models—$49/mo and $99/mo with 5000 email credits/month and unlimited email credits/month, respectively. 

Platform

Web-based 

8. Copymatic

Copymatic email subject line generator

Copymatic generates email subject lines to attract your audience using artificial intelligence in seconds. 

It's trained with over 8 million emails and uses smart AI algorithms and machine learning to generate engaging email subject lines that make your recipients click. It requires you to choose the desired language, tone of voice, level of creativity (regular or high), product name, audience, and product description (with a word limit of 400 words) that generate subject lines that increase clicks and boost conversions. 

You can also select the number of email subject line results you wish to generate using this tool. 

Pros 

  • Lets you generate subject lines in more than 20 languages, including English, Hindi, French, Spanish, and German
  • Generates plagiarism-free subject lines
  • It's CTR optimized, meaning it helps deliver catchy subject lines that grow your open rates

Cons 

  • Comes with minor spelling errors
  • The trial version comes with only 10 credits

Pricing 

Free, and the Starter and Pro plans cost $19/mo and $32/mo, respectively

Platform

Web-based 

9. Storylab.ai

Storylab.ai email subject line generator

StoryLab.ai helps you generate content ideas for several use cases, such as blogs, advertisements, social media captions, and email subject lines. 

It uses artificial intelligence to generate unique email subject lines based on the query you enter. For example, it requires you to enter your topic and the company and product description and get subject lines for your content and email marketing campaigns. 

Pros 

  • Easy to use and beginner-friendly
  • Great tool for short-form content marketing, like email subject lines and blog titles
  • New features and improvements are added regularly

Cons 

  • Provides only 15 free runs

Pricing 

Free, and the Starter, Pro, and Unlimited plans cost $7/mo, $20/mo, and $27/mo, respectively

Platform

Web-based 

10. Headline And Subject Line Generator by Google 

Google Headline and Subject Line Generator

The Headline and Subject Line Generator is an extension offered by Google that lets you choose from 500+ unique subject line and headline combinations. 

You can use this extension straight from your Google account. You can switch from the 'Swipes' and 'Headlines' buttons on the top corner. The Swipes tab offers four categories—List, How To, Question, and General. 

Just enter a noun or a keyword suitable for your email subject line and click on the 'Show Me' button to see a bunch of subject line suggestions in each of the four categories. 

Similarly, the Headlines tab offers four categories—Email Series, Promos, Blogging, and E-commerce, which offer general suggestions, and you can't enter your noun or keyword in this tab. 

Pros 

  • Generates grammatically accurate subject line suggestions

Cons 

  • The suggestions are quite basic, and you can't control their tone of voice

Pricing 

Free 

Platform

Web-based 

How to write an effective email subject line in 3 easy steps

Step 1: Keep It Short and Sweet

The first step is to ensure your subject line is concise. Aim for fewer than 50 characters as most email providers shorten subject lines that are too long. This brevity ensures the essence of your message is immediately visible to the recipient, increasing the chance it captures their attention amongst a sea of other emails.

Step 2: Make It Relevant and Specific

Your subject line should clearly reflect the content of your email. Be specific about the topic, purpose, or action required, so the recipient knows exactly what to expect upon opening. Tailoring the subject line to the recipient's interests or needs can significantly boost open rates.

Step 3: Create a Sense of Urgency or Curiosity

Finally, incorporating a sense of urgency or curiosity can encourage recipients to open your email. Phrases that imply time sensitivity ("Limited offer", "Last chance") or spark curiosity without being too vague ("Secrets to unlocking...", "You won't believe this...") can be effective. However, it's crucial to maintain authenticity and not mislead the recipient, as trust is paramount.

Generate the best email subject lines 

Your email subject lines play a major role in the success of your email marketing campaigns, as they're the first thing your recipients notice about your emails. 

So, if you struggle to come up with interesting, attractive, and conversion-optimized subject lines or simply need some inspiration—check out the email subject line generators mentioned in this article. 

Jasper offers a brilliant email subject line template that compels recipients to open emails with the eye-catching subject lines it generates.\

Sign Up with Jasper today to create subject lines that drive results for your marketing campaigns.

Meet The Author:

Krista Doyle

Krista Doyle

SEO at Jasper

Krista Doyle is a writer-turned-strategy-nerd based in Austin, TX. By day she manages content strategy and SEO right here at Jasper, by night she binges Netflix or continues her mission to find the best old fashioned in Austin, TX.

Marketing Strategy

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