Do you struggle to get prospects to open your emails? For some people, writing clever, witty, clickable subject lines can be a challenge -- and that's where subject line tester tools can come in.
Check for spam triggers, get suggestions for making your subject lines more emotive, and get an overall grade on how clickable your emails are.![Download Now: 50 Sales Email Templates [Free Access]](https://no-cache.hubspot.com/cta/default/53/be67aa79-8dbe-4938-8256-fdf195247a9c.png)
In this post, we'll run through tools to improve you email subject lines for better clickability and deliverability to get more replies from more prospects.
Email Subject Line Tester Tools
- Test Subject
- Email Subject Line Grader
- Spam Check
- Touchstone
- Refine
- SubjectLine.com
- ISnotSPAM
- Headline Analyzer (CoSchedule)
- Hemingway App
- Free Email Subject Previewer
- Emotional Marketing Value Headline Analyzer
- Email Subject Line Keyword Checker
- Is Not Spam
- Email Spam Tester
- Attrock
- Unspam
1. Test Subject by Zurb
What it tests: Appearance on mobile
- Price: Free
Want to know how your sender name, subject line, and pre-header text will appear on the most popular mobile devices of the moment? This tool gives you an instant preview of how copy will appear to your audience. You know, for those moments you want to avoid someone’s iPhone 6 turning “Products for foolproof marketing” into “Products for fool …”.
2. Email Subject Line Grader by Net Atlantic
What it tests: Overall effectiveness of copy, word count, word mixture and balance, and type
- Price: Free
Receive an overall numerical score on how compelling your subject line is, along with suggestions on how to improve it. You’ll also learn how close your character and word count are to the ideal length (50-65 characters or six-to-seven words).
And, find out how your word mixture and balance measures up. Need a little more emotion, action, or power? Subject Line Grader gives it to you straight.
3. Spam Check by Postmark
What it tests: Overall spam score
- Price: Free
You spend time crafting your emails, and you don’t want them to get caught in someone’s spam folder, right? Copy and paste your subject line, pre-header text, email message, and sign-off into this tool, and find out exactly what will trigger spam filters and trap your emails in “The Upside Down.”
4. Touchstone
What it tests: Subject line effectiveness, segment testing, full reporting dashboards, access to Touchstone’s database
- Price: Essential, $69; Expert, $99; Enterprise, $297
This is a deluxe tool that’s probably best for whole teams rather than individuals. Depending on your tier, you’ll receive subject line testing functionality, email reporting, segment testing, filter options, and technical support.
You can also compare your results with those of the 21 billion emails stored in Touchstone’s database.
5. Refine by Moosend
What it tests: Optimize open rates by industry average
- Price: Free
6. SubjectLine.com
What it tests: Overall copy effectiveness
- Price: Free
This tool doesn’t beat around the bush. Get an overall score for your subject line, see where and why you lost points (i.e., “Does not contain a sense of urgency” -15 points), and advice for how to make it better.
7. ISnotSPAM
What it tests: Spam phrases, sender-ID check
- Price: Free
Send your email to the address provided in their homepage and receive a comprehensive spam report in return. This tool flags wording or phrases in your subject line and email body that will trip spam filters. It also checks that your own ID is clean, and suggests fixes for any spam-related issues that arise.
8. Headline Analyzer by CoSchedule
What it tests: Overall copy effectiveness, word balance, length analysis, keywords, type, and sentiment
- Price: Free
This tool was built to analyze blog/article headlines, but it works just as well for subject lines. Headline Analyzer gives you an overall headline score and provides tips on structure, grammar, and word placement.
Widely considered the gold standard in headline testers, this is definitely a tool to keep in your back pocket.
9. Hemingway App
What it tests: Readability of copy
- Price: Free
Not a literature buff? Legendary author Ernest Hemingway was known for his straightforward writing style. There were no warm sunset walks festooned with bright spring blooms in his books. Hemingway would have written, “We took a walk. It was warm. The flowers were in bloom.”
This app is helpful for editing the body of your email. Copy and paste your follow-up email into this tool to get an overall readability grade, find out where you’ve used passive voice, if you have too many adverbs, and which sentences are hard to read.
10. Free Email Subject Previewer by EmailTooltester
What it tests: How your subject line will appear on various mobile devices
- Price: Free
Ensure your emails stand out to your audience with EmailTooltester’s Email Subject Line Tester. You can test your sender name, subject line, and the first few lines of your email to improve the success of your email campaign. You can test on the following devices before sending:
- iPhone 14
- iPhone SE
- iPad (10th gen)
- Google Pixel 7
- Samsung S22 Ultra
11. Emotional Marketing Value Headline Analyzer by The Advanced Marketing Institute
What it tests: Emotional Marketing Value (EMV) words
- Price: Free
Did you know 20% of the English language is made up of EMV words? Find out if your headline appeals to the intellectual or empathetic side of your prospect’s brain, and learn which side you want to appeal to given the goals and content of your emails.
12. Email Subject Line Keyword Checker by Adestra
What it tests: Open rate and click rate of subject line keywords
- Price: Free
This tool asks you to select a business sector and type in your keyword -- the main point of your subject line. For example, if my email subject line is, “Checking on contract status” I would type in “Contract” as my keyword.
In this case, the tool would tell me open rates are .35% below average for emails using the word “contract” in the subject line. Given this information, I might choose a different subject line keyword.
13. Email Subject Line Analyzer by Attrock
What it tests: Subject line’s readability, sentiment, word/character length, and overall effectiveness
- Price: Free
Want to check how compelling your subject line is?
This tool will score your subject lines and provide useful tips for improving them to increase email opens and clicks. The Email Subject Line Analyzer is designed to assess and score your subject line based on its click potential. It also helps you optimize your subject line’s length and emotional appeal to increase clicks.
Email Spam Checker Tools
Email spam checker tools scan your subject lines and email copy so they won't get automatically marked as spam and downgrade your email deliverability.
14. Is Not Spam
What it tests: If your email triggers common spam filters
- Price: Free
Is Not Spam has you actually send your email draft to them, and they deliver a report within a few minutes, grading everything from your subject line, email body copy, and HTML code for deliverability, with specific suggestions for improving it if it doesn't make the cut.
15. Email Spam Tester
What it tests: If your email triggers common spam filters
- Price: Starts at $39/month
Like Is Not Spam, but with paid features you can share with a team and track over time, Email Spam Tester conducts a thorough grading of all elements of your email drafts and gives you guidance for how to improve them.
16. UnSpam Email
What it tests: If your email triggers common spam filters and deliverability testing
- Price: Free, starts at $9/month
UnSpam email is an email spam and email deliverability tracker that helps boost your email marketing campaigns by preventing email blacklists and improving accessibility. By checking and monitoring your IP and domain, UnSpam can notify you if your emails are automatically being blacklisted to your customers' spam inboxes. In addition, you can ensure your emails are aesthetically through their email preview tool to prevent any poor-performing emails from hurting your reputation. UnSpam even comes with an eye-tracking prediction heatmap to make sure every campaign has accurate depictions of what your customers like and interact with.
Subject lines are the most important part of your email. In fact, 33% of email recipients report opening emails based on the subject line alone. Make the most of inbox attention, and ensure subject lines grab your prospect’s eye every time.
To learn more, read about managing multiple inboxes in Gmail next.
