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Hey there! Let me start off by answering a question likely top of mind – what exactly are email subject lines and subject line testers?
Email subject lines are short summary descriptions that appear next to an email sender‘s name when messages arrive in a recipient‘s inbox. They concisely communicate key details to compel opening and reading.
Subject line testers allow senders to experiment with multiple variations of a subject line to determine which version elicits the highest open rates when deployed to their subscriber list.
Now that we‘re on the same page with terminology, let‘s dive deeper into why mastering subject line testing is so critical for your email program‘s success.
Why Properly Testing Email Subject Lines Matters
We all hate spam and likely quickly delete irrelevant emails without a second glance. Your contacts feel the same way about your messages cluttering up their inbox.
Standing out is no easy task. With 306.4 billion marketing emails sent daily, fierce competition for readers‘ fleeting attention is an understatement.
But there is good news according to recent studies!
Email still boasts higher conversion rates than other channels when done right. And compelling subject lines play a major role in improving email performance.
Let‘s look at some revealing statistics:
- Well-optimized subject lines can achieve up to 50% open rates based on data from Mailchimp
- Subject lines employing personalization see open rates increase by 26% on average
- Emails with subject lines focused on solving problems increase opens by 29%
- Subject lines in the form of questions see opens improve 17% over statement formats
And remember – open rates represent the key hurdle to clear before a contact even begins reading your carefully crafted email content.
The subject line testing tools covered in the next sections will help you identify your highest performing options, landing more opens.
Now let‘s overview the key elements to test within a subject line when running experiments.
5 Key Email Subject Line Areas to Test
While simply personalizing names can lift open rates substantially, it merely scratches the surface of subject line optimization. Here are five impactful elements worth testing:
1. Subject Line Length
Industry research shows subject lines with between 5-10 words achieve the highest open rates. With inboxes largely viewing on mobile devices, going beyond 10 words risks vital information getting cut off or not rendering at all.
But keep in mind that sentence structure or descriptive capabilities may suffer if you trim too aggressively. Find the right balance for conveying an engaging essence within 5-10 words.
2. Questions vs. Statements
Subject lines styled as questions invite curiosity, thus improving open potential. The hope is recipients will open seeking answers.
But you need not be overly direct or dull simply stating something like "Question about X". Craft questions in a thought-provoking manner that compels engagement. Think about what your audience cares about as you shape question variations to test.
3. Problem Identification
We all love shortcuts and solutions to nagging problems. Call out subscriber pain points to portray your email as a panacea for their troubles through subject lines.
Studies show that clearly articulating questions around problems in subject lines lifts open rates 29% higher than generic statements. Ensure you know your customers‘ real issues before crafting problem-focused subject line testing variants.
4. Sense of Urgency
Countdown timers, limited offers and other tactics inducing urgency work well across marketing channels and email is no exception.
But beware rider overusing such urgency elements in your subject lines. With too many "last chance" offers, you risk subscribers dismissing them as disingenuous. Use only for truly special occasions vs. all deployments.
5. Emotional Triggers
Words that spark excitement, surprise, curiosity and other emotions appear frequently in top-performing subject lines.
Try weaving in emotionally-charged verbs and adjectives such as "announcing", "introducing", "behold" etc. to add flavor around things you truly expect to elicit reader intrigue.
Let‘s now explore tools that allow easy subject line testing across these elements and more with their real subscriber lists to determine optimal resonance.
Top 10 Email Subject Line Testing Tools
Suffice it to say, you could spend forever manually editing subject lines and guessing at impact on open rates.
The following specialized tools introduce efficiencies through automated subject line evaluations and pre-deployment test sending.
I‘ve ordered recommendations descending from advanced paid offerings to completely free options so you can assess the best solution matching needs, budget and technical capabilities.
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| Tool | Key Benefits | Price |
|---|---|---|
| Touchstone | Predictive subject line performance modelling, advanced analytics | From $499/month |
| SendCheckIt | Deep subject line assessment across 16 metrics, inbox previews | Free & paid plans |
Now let me provide more details around the top recommended subject line testing solutions across both paid and free tiers.
1. Touchstone
Touchstone is an enterprise-class email testing solution leveraged by major brands like Target, Microsoft and Chase.
The tool‘s proprietary predictive algorithms and deep performance data analysis accurately model how test subject lines will perform when deployed to full email lists.
You get a sophisticated segmentation system for sending subject line variants to precise customer groups along with comparative metrics to identify the best option.
And an intuitive analytics dashboard provides engagement and open rate reporting visualizations across all tests.
In summary, Touchstone is the gold standard for serious email senders who rely heavily on maximizing subject line opens.
It costs more but delivers predictive insights and robust analytics unavailable in free alternatives.
Main Benefits:
- Predictive subject line performance modelling
- Powerful behavioral consumer data filtering
- Complete test automation flows
- Full analytics and reporting dashboard
Price: From $499/month based on list size
2. SendCheckIt
SendCheckIt offers one of the most thorough free subject line assessments, analyzing across 16 critical attributes including readability, spam potential, emotional sentiment and click-worthiness.
It provides an overall effectiveness score along with ratings across each specific metric. I especially appreciate the visual inbox previews illustrating exactly how your test subject lines will appear within major email providers.
This helps identify formatting issues that undermine opens. You receive 5 free subject line tests monthly in the free version with additional assessments requiring reasonable paid plans.
For the deepest analysis along with inbox optimzation, SendCheckIt is a leading contender.
Main Benefits:
- Evaluates subject lines across 16 key metrics
- Visual inbox previews highlight formatting issues
- Free monthly tests or affordable paid plans
Price: Free or paid plans starting at $6 monthly
3. CoSchedule Headline Analyzer
While designed primarily for testing blog post titles and headlines, CoSchedule‘s analyzer tool proves very handy for email subject line optimization as well with detailed scoring around emotional word usage, readability, and spam detection.
It tags words eliciting positive and negative emotions within your test subject lines, empowering easy tweaks to word choice for maximizing compelling feelings. An overall grade summarizes potential punchiness.
I‘m also a major fan of the mobile preview highlighting exactly how subject lines render on smartphones and tablets. We all know smaller devices dominate email access these days.
For easy emotional and mobile optimization, Headline Analyzer warrants consideration.
Main Benefits:
- Emotion-focused word tagging and scoring
- Readability and spam filtering assessments
- Mobile preview across devices
Price: Free
4. Advanced Marketing Institute Headline Analyzer
Similar to CoSchedule above, this analyzer tool concentrates specifically on the emotional sentiment projected within test subject lines.
It leverages principles of "emotional marketing value" to categorize words triggering feelings ranging from happiness, anxiety, anger and more.
Scoring runs on a 100 point scale with any score over 60 considered emotionally captivating and likely to compel opening. This novel emotional analysis alone makes it a beneficial free addition for subject line testing.
Main Benefits:
- Emotional Marketing Value scoring
- Sentiment analysis by emotion type
- Comparison showing intellectual vs emotional words
Price: Free
5. Mizy by Automizy
Mizy offers a unique approach I‘ve yet to see matched in other testers. You first draft full email content. The tool then analyzes message copy through Natural Language Processing to intelligently recommend highly relevant subject lines for selection or further refinement.
This allows ensuring strong title-to-content harmony – a major ranking factor in spam filters when assessing relevance. Beyond automated suggestions, Mizy provides curated subject line templates categorized across common email types.
The AI matching and expansive idea library make Mizy worthwhile, especially given its free access.
Main Benefits:
- AI-powered subject line recommendations engine
- Analyzes full email copy to identify optimal titles
- Extensive subject line templates searchable by category
Price: Free
6. Omnisend Subject Line Grader
Omnisend takes a simplified approach, providing an overall letter grade assessing expected subject line effectiveness. Grading covers key elements like spam probability based on commonly filtered words, length in comparison to performance benchmarks, scannability based on hard-to-read long words, and other key metrics.
It won‘t supply the rich stylistic or emotional analysis of other tools mentioned. But for a general second-opinion scoring before launch, Omnisend fills this basic need.
Main Benefits:
- Singleoverall letter grade rating
- Considers length, spam potential and readability
- Very simple and free
Price: Free
7. Email Subject Line Grader
As the name suggests, this grader focuses exclusively on email subject line assessment, making it another easy way to garner a second opinion scoring.
It analyzes based primarily on proper subject line length, categorization of style format like question, list etc, along with review of word types leveraged for impact and engagement.
I appreciate the straightforward approach and specific tips provided to fix identified shortcomings. Well worth adding to your general optimization toolkit.
Main Benefits:
- Quickly assesses subject line length, format and content
- Identifies improvement areas
- Very easy to use interface
Price: Free
8. Zurb TestSubject
TestSubject takes a decidedly singular, but important, focus – rendering previews of exactly how your test subject lines will appear on various mobile devices.
Given email predominately gets opened on smartphones these days, understanding mobile appearance proves critical to minimize awkward truncation or poor visibility.
Currently supported preview options include iPhone, Samsung Galaxy among other devices with more likely coming. For mobile-centric lines review, TestSubject fills this need completely free.
Main Benefits:
- Models subject line appearance across mobile devices
- Supports iPhone, Samsung Galaxy, Google Pixel and more
Price: Free
9. Subjectline.com
Last but not least, I felt compelled to include the appropriately named Subjectline.com tool for sheer depth of algorithmic subject line quality checks…over 800 to be exact!
It scans for issues compromising deliverability, engagement and spam probability, calling out problems in clear improvement-oriented buckets. Given emailynamism, continual updates ensure the latest filter factors get incorporated.
For free users, you can evaluate one subject line daily with additional capacity requiring affordable subscriptions. If wanting the deepest automated error-checking, give Subjectline.com a look.
Main Benefits:
- Over 800 deliverability, engagement and spam checks
- Calls out issues in actionable improvement buckets
- Affordable paid plans to increase assessments
Price: Free or paid plans starting at $8/month
Best Practices For Subject Line Testing
I hope reviewing the key subject line optimization elements along with top tester tools provides a helpful starting point for seriously improving email open rates.
As we wrap up, I wanted to offer a few more universal best practices to keep in mind:
Invoke Intrigue & Curiosity
Compel engagement by asking thoughtful questions or presenting incomplete ideas that prod readers to open seeking answers.
Go Easy on Urgency Tactics
While countdowns and limited offers work, excessive usage trains subscribers to ignore such language.
Keep Critical Info Concise
Review lines verbose beyond 10 words to ensure key details aren‘t cut-off, especially on mobile.
Personalize Responsibly
Add first names, locations etc. to boost relevancy but don‘t get too informal. Stay professional.
Appeal to Emotions
Weave in exciting verbs and adjectives like "announcing" or "introducing" to pique interest.
Always Test New Concepts
Even subject lines closely following best practices should get validated with a subset of contacts to confirm performance prior to full email launch.
So there you have it – a fully packed guide covering why subject line optimization and testing matters, what elements to focus experiments on, the top tools to assist, and best practices to further improve efforts.
Whew…that was a lot! But I sincerely hope all the tactical recommendations prove helpful fueling your email marketing program‘s continued success.
Please drop any outstanding questions in the comments section below!