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a screenshot showing the mailmeteor email subject line tester

4 free email subject line testers (rated)


Julie here:

If you're looking to improve the effectiveness of your email subject lines, you might consider using 1 or more of the 4 tools I regularly use. These testers are useful, free, and super fun!

Each tester rates your email subject line somewhat differently, so I like to get feedback and ideas from multiple tools.

I took the following fundraising appeal subject line and entered it into each of the 4 testers:

⏳ Do you have 1 minute to protect wildlife?


Here are the 4 subject line testers in action:

🚀 Mailmeteor Subject Line Tester: Your Personal Brainstorming Bot Buddy!

This tool does two cool things. First, it gives you a score with an overview of areas for improvement.

Second, it has GPT-3 🤖 embedded into the form to give you 5 alternative email subject lines. I glance at each AI-generated suggestion for any new word choice or word arrangement that may sound better.

🚀 SendCheckIt Subject Line Tester: So Many Tips Here!

This is definitely one of the most helpful subject line testing tools I’ve found. It rates so many areas — like 17-ish 😮 — such as grade level, scannability, length, sentiment, emojis, personalization, and punctuation.

It not only tells you WHAT could be improved but it also tells you WHY.

🚀 Coschedule Subject Line Tester: Graphics Galore!

I like this tool because the results are presented in an info-graphics sort of way. It always seems to identify multiple areas of improvement — and even shows what your subject line will look like on multiple devices.

Plus: the tool cheers you along ("Hey, rock star" and "Getting c-l-o-s-e-r! “) which makes me smile big. 😄

🚀 SubjectLine Tester: My Favorite!

This rating tool is gamified, which makes it both informative and fun! You get points added or subtracted based on elements that meet industry standards for effective email subject lines.

I enjoy tinkering with my subject line to get a higher score. I feel a huge accomplishment when I get extra credit points that push my score over 100! (😂)



While you're here...

Why not read a little more?

Here are a few more blog posts you might like:

1. Thank You for the "Mental Real Estate"

2. You Can't Feel "Empty Urgency"

3. X-ray of a Donor Newsletter -- "Know Your Bones"

4. You Can't Get Donors to FEEL It If You Don't Feel It First

5. What to Put in Your Donor Newsletter



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