Best Readability Checker

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Candace Osmond

Candace Osmond studied Advanced Writing & Editing Essentials at MHC. She’s been an International and USA TODAY Bestselling Author for over a decade. And she’s worked as an Editor for several mid-sized publications. Candace has a keen eye for content editing and a high degree of expertise in Fiction.

Aiming for content readability will improve the likelihood of your online content getting more engagements and conversions. It also reduces misunderstandings and exit rates on your website.

If you’re looking for the best readability checker, here are ten tools that will improve your content for SEO. These checkers analyze your readability scores, keyword distribution, and formatting. 

Best Readability Tools to Check Your SEO Content

SEMrush SEO Writing Assistant


SEMrush ensures you produce the most SEO-optimized piece of content through its own scoring formula. This score is based on your word count, tone of voice, and readability. The content readability tool allows you to adjust your preferred content readability.

For example, SEMrush lets you personalize your tone from casual to formal. Take advantage of the app’s content keyword recommendations. Content creators can insert the 20+ phrases made by SEMrush in every sentence for high rankings on search engines.

SEMrush SEO Writing Assistant has a paragraph rephraser in its beta version. The AI algorithm will produce a simplified version of your text, which you can use on your online post. But it has a limit on character count, so it’s not recommended for long-form content. 

Download the MS Word Add-on to access your readability scores on the application. It will help you craft SEO-friendly content on the word processor without switching between editors.

Yoast SEO for WordPress

Yoast SEO

Yoast SEO for WordPress should be part of all digital marketers’ and content writers’ content strategies. Make sure you produce top-ranking content through Yoast’s variety of content writing tools, such as:

  • Flesch reading ease.
  • Subheading distribution.
  • Sentence and paragraph length.
  • Transitional devices.
  • Passive and active voice.

These scores determine how effectively content engages with your intended audience. For example, light and casual blog posts should have an 8th-grade reading level.

Competitive content writers understand the importance of the technical aspect of online writing. Yoast will help you with this dimension. Try the premium plugin to observe proper keyword density, avoid dead links, and receive URL suggestions. 

Yoast can identify your keywords’ related keyphrases, synonyms, and other word forms. This feature lets you write more naturally without compromising your rankings. You can also add structured data for Google to understand your website.

SearchMetrics Content Experience


SearchMetrics Content Experience makes the digital content process for optimization easier. It gives you the exact numbers for your word count, keyword coverage, phrase repeats, and other relevant information.

The science of SEO content is at the heart of this tool, as it scans your entire content for readability. It understands that the ease of understanding content also depends on formats. SearchMetrics offers ready-formatted HTML codes so you can quickly export your content.

Other robust content marketing tools include content scores, keyword finder, and question finder. The question finder is perfect for writing an FAQ on your piece of business content or blog post. This ensures you’re writing Google-relevant questions and answers.

WebFX Readability Tool


WebFX Readability Tool’s features provide a focus for content editors who want to produce well-optimized content with high SEO rankings. It will give you reports of popular readability formulas, including:

  • Coleman-Liau Index score.
  • Flesch Reading Ease.
  • SMOG Index.
  • Flesch-Kincaid grade level.
  • Gunning Fog Score.
  • Automated Readability Index.

These six scores should be enough to help users make online reading more convenient for their audience. Aside from giving the content score, WebFX also tells more information about complex words, sentence count, and syllable counts.

You can directly type your text on the website or copy and paste the entire content. You can also enter the URL for content readability testing.

One downside to WebFX Readability Tool is its inability to spot complex sentence structures. It also won’t give you detailed suggestions on making your content clearer and more straightforward.

Automatic Readability Checker

If you’re a content user looking for a free text readability calculator, this Automatic Readability Checker is the right tool. It’s a tool that uses many formulas to determine your readability level and reading age. 

Just enter your text, and click “Check Text Readability.” The tool will check for the following:

  • Flesch Reading Ease.
  • Flesch-Kincaid Grade level.
  • FOG Scale.
  • Coleman-Liau Index.
  • Linear Write Formula
  • Automated Readability Index.
  • SMOG Index.

These typical reading scores will help you know whether your writing needs adjustments or not. For example, if your target audience comprises advanced readers, a Flesch-Kincaid level of eight might be too low.

Readability Analyzer

Readability Analyzer is an online tool that only focuses on popular formulas for your reading level or ease. This analyzer gives you insights on your Flesch-Kincaid Grade Level, SMOG, Flesch Kincaid Reading Ease, Fry Readability level, and more.

The score checker doesn’t help you turn the passive voice into the active voice. It also won’t detect the variety of sentence structure, and complex and lengthy sentences. 

Instead, it evaluates your content by grade level and gives you your word count and percentage of difficult words.

The readability score checker gives your individual content an overall content readability score. Take note of these numbers to know how to practice content stability in your writing.


Tone Detection

Grammarly does not necessarily improve your content readability for SEO. Instead, it provides feedback on your grammar, spelling, sentence structure, and sentence variety for any writing. Use this tool if you need help enhancing your vocabulary or want sentence variety.

Grammarly provides alternative words to repeated words and phrases in your writing. It ensures these word suggestions are context-specific to keep your document human-sounding.

This AI writing tool also addresses issues in your tone. First, you need to set the goals for your writing. Select your formality, intent, audience, and domain to get genre-specific suggestions for your text.

You can modify your text to be more inclusive, confident, and respectful. It’s the only editing tool that can give in-depth explanations for its suggestions, helping you become a better writer.

Subscribe to Grammarly Premium if you need access to the plagiarism checker and other advanced grammar reports. 

Hemingway App

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If you need a more straightforward online writing editor for your text, check out Hemingway App. Unlike Grammarly, Hemingway doesn’t address your typos, spelling mistakes, and grammatical errors. Instead, it only focuses on the readability aspects of your writing.

Hemingway highlights lengthy sentences, complex phrases, and hard-to-understand sentences in your writing. It also highlights any sentence with the passive voice and overused adverbs.

All these tools are detected by the online editor using a color-coded system. For example, blue highlights indicate adverbs that weaken your sentences. You need to remove them and pick stronger ones. 

Hemingway App also shows the following:

  • Reading time.
  • Letter count.
  • Character count.
  • Word count.
  • Sentences.
  • Paragraphs.
  • Reading grade level.

The application also provides a few formatting options you’ll likely find on blog platforms. Download the premium version of Hemingway if you want to work offline or publish your work directly to WordPress.

Bulk SEO Tools

Many readability checkers and online text editors forget that formatting plays a significant role in content readability. Bulk SEO Tools will help you enhance the overlooked formatting of your writing.

It won’t help you with your incorrect grammar or keyword distribution. But it addresses your content layout in bulk. For instance, a considerable part of your text might be in uppercase. Bulk SEO Tool lets you enter the text in the case converter to fix which ones need to be capitalized.

Bulk SEO Tools has a dated interface. But it still proves helpful in removing duplicated, extra spaces, tabs, and lines. 

Are Readability Tests Accurate?

Readability tests are helpful but not 100% accurate. Even though online content writers, schools, and businesses use these tools, there are many reasons why you shouldn’t entirely rely on them for your writing.

They Don’t Consider the Definition of Words

For your target audience, “anaphylaxis” might be a familiar word. But for your Flesch-Kincaid scores, the term is unclear or complex. Some formulas also count word length, which might be odd for writers who use common words like “acquitted” and “technique.”

Grade Levels Don’t Mean Anything to Adults

Why do you aim for a 9th-grade reading level if you write for adults? A ninth-grader who understands your adult-oriented writing is a very fluent reader. But for adults, even a 12th-grade reading level is easy to understand.

Good Scores Don’t Necessarily Mean High SEO Rankings

A good readability score does not automatically mean you’ll rank high on Google’s results pages. You also need to consider how you naturally inject keywords into your writing. Are you using internal links, tags, and metadata for your content?

Be Content with Your Content

Readability scores and reading grade levels give you an idea about the simplicity and understandability of your writing. They help you spot and solve issues with your document to better engage with your target audience. 

The best readability checker will help you optimize your content for SEO. Choose one that includes methods like Flesch-Kincaid Grade Level, Coleman-Liau Index, and the SMOG Index.