Writing compelling and conversion-focused email subject lines is not easy. It’s the first thing your recipients see or notice, so it must be persuasive.

Successful email marketers spend most of their time writing a subject line. It must attract readers’ attention and force them to read your email body. It gets you more click-through rate and boosts sales from emails.

Why are Email Subject Lines Important?

An email marketing campaign’s open rate determines its success. 

According to a recent study by Smart Insights, only 17% of emails are opened by recipients. So just looking at the open rate metric, you can gain a complete picture of your campaign performance.

A good subject line is one of the essential email marketing factors that people overlook. It’s a good subject line that intrigues people to open your email or move it to spam without reading the email.

Another factor is the frequency with which you send emails. If you send too many, people will start to ignore them. But if you don’t send enough, people will forget you.

In successful email campaigns, the focus remains on getting a high open rate which is why subject lines are so important.

What are Email Subject Line Generator tools?

Email subject line generator tools are offered mainly by email marketing SaaS providers to help you generate engaging subject lines.

These companies deeply understand the email marketing industry, and their research is backed by data. Using their data, they apply artificial intelligence to get better email subject lines.

Since email subject lines determine open email rates, getting attention from your target audience at the first instance becomes crucial.

Here are a few benefits of using email subject line generator tools:

Fast Results: Using subject line tools help you come up with new ideas faster.

Technology: Since most tools use artificial intelligence, they’re backed by huge amounts of data.

Free: Most email subject line generator tools are free, or you need to sign up for their platforms to use them.

Type: You get the option to select the type of email subject lines depending upon the emails you want to deliver.

Tone: Many of these tools allow you to set the tone of your subject lines. For example, you can select the tone to be friendly, professional, urgent, story-telling, personalization, coupons, and more.

Finally, the content of your email is also important. If your emails are interesting and relevant, people will be more likely to open them. But if they’re boring or full of spam, people will quickly lose interest.

Best Email Subject Line Generator Tools

Now that you know the importance of email subject lines for email marketing campaigns, let’s check how you can create them quickly with readymade tools.

Here is a list of email subject line generator tools:



Copy.ai is a copywriting tool powered by artificial intelligence technology. Copy.ai is mainly a tool to create articles, but it helps with email subject generation as well.

Copy.ai also provides ready-to-use email templates for follow-up emails, cold emails, and thank you emails. It also has a free email subject line generator that helps you craft AI-powered subject lines for email newsletters and promotional emails.


Once you login into Copy.ai, you’ll find the email subject line tool in their toolbox. After selecting this option, you’ll be asked to add product or promotion information.

Based on your details, the tool provides you with a list of ideas for subject lines. You can generate more ideas by clicking on the “Make more” button and the subject lines to your list.



Frase.io is an AI content writing platform that helps you write AI-optimized content articles and posts in minutes.

Once you log in, you’ll find various content generator tools like AI content generator, blog outline generator, article introduction generator, blog title generator, and many more.

Frase.io has an email subject line generator that helps create engaging subject lines. Just enter the main keyword or topic, and their AI writer will suggest subject lines that you can use for your campaigns.

Frase’s tool is free and passes plagiarism checks to ensure you get unique content every time. However, getting the AI-generated content checked from a plagiarism checker tool like Grammarly or Copyscape is a good idea.

ActiveCampaign Generator


ActiveCampaign is a popular email marketing service provider. They offer all the features for creating successful email campaigns, like marketing automation, integrations with CRM, email segmentation, and readymade email templates.

Being a prominent leader in the email marketing industry, ActiveCampaign understands the value of crafting engaging email subject lines, and therefore it offers a free email subject line generator tool.

The tool is easy to use. You need to specify the keyword category type and enter your keyword. For example, we entered Blogging as our keyword, and the category is beneficial.


Based on our inputs, here are the generated email subject lines. You can experiment with different keyword categories and generate as many subject lines as you want.



Reply.io is a sales enablement platform that automates the work of finding email addresses, integrating with CRM platforms, and generating analytics reports for businesses.

It helps you with your inbound and outbound sales email engagement, automates lead nurturing, and tracks sales performance reports.

Reply.io offers a free cold email subject line generator similar to ActiveCampaign’s generator. You can select the category type from the four different options provided and enter your preferred keyword.


One add-on is the personalized category that lets you specify your prospect’s name, company details, and company name. It helps you provide a personalized touch to your prospect.



Keap, formerly InfusionSoft, is a CRM automation software that helps you collect leads, nurture them, and close sales. It offers pre-built templates for email marketing, landing pages, and newsletter broadcasts.

Keap has a free and easy-to-use email subject line generator available on their website.


Unlike other generators where you select a category, Keap provides options for choosing the message type. For example, you can select an email type from the below list:

  • Newsletter,
  • Re-engagement,
  • Follow-up,
  • Promotional email,
  • Resources,
  • Registration.

After choosing the email type, it’s time to enter your target audience, set your keyword, and the end result one needs to achieve after reading your email.


Based on your inputs, you get various email subject lines that you can copy to your campaigns.



Encharge is an email marketing automation tool that helps you segment email lists based on user interactions on your website. You can easily create a series of emails, nurture leads, onboard clients, and automate your sales tasks.

Based on natural processing language, encharge.io offers a free email subject line generator. It takes in 3 input types: the email topic, your company’s name, and your email’s tone.


The email tone input field has many options, such as friendly, professional, formal, funny, urgent, and more. In response to your inputs and email topic, you receive many email subject lines for your email campaigns.


SalesBlink is a B2B lead generation tool that helps you find the prospect email, send cold email outreach, make calls, and track lead conversions in a single platform.

You can integrate SalesBlink with LinkedIn and customer CRM systems to connect with potential customers and send readymade yet customizable messages to get leads.

With SalesBlink Free cold email subject line generator, you can easily write email subject lines that help you get more open rates. One of the best things is that you can use these subject lines directly in your SalesBlink cold emails and avoid the copy-paste step.



Storylab.io is an online content generation tool that helps you write engaging stories with a readymade copy for your marketing needs.

Storylab’s email subject line generator uses natural processing language (NLP) and artificial intelligence to generate engaging subject lines that help you get more open rates.


The platform is relatively easy to use, and you need to specify the type of copy, your preferred topic, and its description and enter a few keywords to generate your copy.

Not only email subject lines, but you also can generate a complete email copy to match your marketing efforts with Storylab’s content generator tools.


Will personalization add value to the subject line?

Personalization in subject lines adds value to your email recipients. It denotes you’re writing a dedicated email to the recipient and not a marketing email that’ll be sent to hundreds of email subscribers.
To personalize the emails, you can also use emojis, symbols, and recipients’ nicknames in the subject lines.

Are email subject generators ideal for newsletters?

Yes, email subject generators can help with ideas for generating compelling email subject lines for newsletters. However, you can tweak them to match the tone to personalize your email subscribers.


Coming up with new email subject lines daily can be challenging. And therefore, these email subject line generator tools can help you with new ideas to try out in your marketing efforts.

These tools will surely help you create more engaging subject lines that will help increase your open rate and conversions.

Further, don’t forget to check out tools to find emails instantly.