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Wondering if your writing is easy enough for your audience to understand?

Get readability scores (Flesch, Gunning Fog) and see how to improve clarity.

Readability Score Calculator

Analyze text readability with Flesch-Kincaid, Gunning Fog, and Coleman-Liau scores

Understanding Readability Scores

Readability scores estimate the education level needed to comprehend a text on first reading. The Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog Index, and Coleman-Liau Index each use different formulas—factoring in sentence length, word complexity, and character counts—to produce a numerical difficulty rating. Writers, editors, educators, and content marketers use these scores to ensure their content matches the reading level of their target audience.

Common Mistakes

  • ✗Writing overly long sentences — aim for 15-20 words average
  • ✗Using too much jargon without explanation
  • ✗Assuming a high reading level matches a professional tone

Pro Tips

  • ✓Target Flesch-Kincaid Grade Level 7-8 for general web content
  • ✓Use short sentences for emphasis, longer ones for explanation
  • ✓Read your writing aloud — if you run out of breath, the sentence is too long

Real-World Examples

Health information

NIH recommends writing at a 6th-8th grade reading level for patient materials

Legal documents

Aim for plain language — many laws now require readability standards

Marketing copy

Keep it at 5th-7th grade level for maximum engagement

Want to learn more?

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About Readability Scores

What is Readability?

Readability refers to how easily a reader can understand a piece of text. It depends on sentence length, word complexity, and sentence structure. Readability scores are numerical measures that estimate the education level a person needs to comprehend a text on first reading.

Writers, editors, educators, and content marketers use readability scores to ensure their content reaches the intended audience. A blog post aimed at the general public should score differently from an academic research paper.

How Scores Work

Each readability formula uses different inputs to estimate text difficulty:

  • Flesch Reading Ease -- Produces a score from 0 to 100. Higher scores mean the text is easier to read. A score of 60-70 is considered standard and appropriate for most adult audiences.
  • Flesch-Kincaid Grade Level -- Estimates the US school grade level required to understand the text. A score of 8 means an 8th grader (around 13-14 years old) should be able to read it.
  • Gunning Fog Index -- Counts words with three or more syllables as "complex" words and factors them into the score. Widely used in business and government writing guidelines.
  • Coleman-Liau Index -- Unlike the other formulas, this one uses character counts instead of syllable counts, making it more reliable for automated analysis where syllable detection is imprecise.

How to Improve Readability

  • Shorten sentences -- Aim for an average of 15-20 words per sentence. Break long sentences into two.
  • Use simple words -- Replace complex vocabulary with common alternatives. "Use" instead of "utilize," "help" instead of "facilitate."
  • Break text into paragraphs -- Each paragraph should cover one idea. White space helps readers navigate content.
  • Use active voice -- "The team completed the project" is clearer than "The project was completed by the team."
  • Know your audience -- A score of 60-70 (Flesch) works for most web content. Aim for 80+ for content targeting younger readers or non-native speakers.

Frequently Asked Questions

What is a good Flesch Reading Ease score?

For general web content, aim for 60-70. For content targeting a broad audience (including non-native speakers), aim for 70-80. Academic or technical writing typically falls in the 30-50 range.

How accurate are readability scores?

These scores are estimates based on formulaic approximations. They measure surface-level features like sentence length and word complexity, not actual comprehension difficulty, logical flow, or subject-matter familiarity.

Which readability score should I use?

Flesch Reading Ease is the most widely recognized. Flesch-Kincaid Grade Level is common in education. Gunning Fog is popular in business writing. Using multiple scores together gives a more complete picture.

Does this tool work with non-English text?

The syllable-counting heuristic is tuned for English. Non-English text may produce inaccurate results. The Coleman-Liau Index is the most language-agnostic formula since it relies on character counts.

This utility is provided for informational purposes only. KnowKit is not responsible for any errors in the output.

Frequently Asked Questions

What is a good Flesch Reading Ease score for web content?

For general web content, aim for 60-70. For content targeting a broad audience including non-native speakers, aim for 70-80. Academic or technical writing typically falls in the 30-50 range.

How accurate are readability scores?

These scores are estimates based on formulaic approximations. They measure surface-level features like sentence length and word complexity, not actual comprehension difficulty, logical flow, or subject-matter familiarity.

Which readability score should I use?

Flesch Reading Ease is the most widely recognized. Flesch-Kincaid Grade Level is common in education. Gunning Fog is popular in business writing. Using multiple scores together gives a more complete picture.

Does this tool work with non-English text?

The syllable-counting heuristic is tuned for English. Non-English text may produce inaccurate results. The Coleman-Liau Index is the most language-agnostic formula since it relies on character counts.

What reading level should I target for health or medical content?

The NIH and AMA recommend writing patient-facing health information at a 6th-8th grade reading level. This ensures the broadest possible audience can understand important health guidance.

Can readability scores help with SEO?

Indirectly. Google's helpful content guidelines favor clear, well-organized writing. Content that scores well on readability metrics tends to have lower bounce rates and higher engagement, which can positively influence rankings.

What's the difference between Flesch Reading Ease and Flesch-Kincaid?

Flesch Reading Ease produces a 0-100 score where higher is easier. Flesch-Kincaid Grade Level estimates a US school grade (e.g., 8.0 means 8th grade). They use similar inputs but express the result differently — one as ease, the other as difficulty.