Readability Checker — Flesch Score & More
Check text readability with Flesch-Kincaid, SMOG, Gunning Fog, and Coleman-Liau scores. See grade level and audience fit. Free tool.
Overall Readability
12th grade
High school level · Flesch Ease: 46 (Difficult)
Flesch Reading Ease
Measures how easy a text is to read on a 0-100 scale. Higher scores mean easier reading.
Flesch-Kincaid Grade Level
Estimates the U.S. school grade level needed to understand the text. Lower is easier.
Audience: High school
SMOG Index
Estimates years of education needed to understand a text. Based on polysyllabic word count (3+ syllables).
Audience: High school
Gunning Fog Index
Estimates the years of formal education needed. Considers sentence length and complex words (3+ syllables).
Audience: College
Coleman-Liau Index
Uses character count instead of syllables for grade level estimation. Based on average letters and sentences per 100 words.
Audience: College
Flesch Reading Ease Scale
About Readability Checker
Readability scores help you understand how easy your text is to read. This tool calculates five established readability formulas: Flesch-Kincaid Grade Level, SMOG Index, Gunning Fog Index, Coleman-Liau Index, and Automated Readability Index.
Each formula produces a grade level indicating the education level needed to understand the text. Use these scores to ensure your content is accessible to your target audience.
Each readability formula uses different text features to estimate difficulty. Flesch-Kincaid counts syllables per word and words per sentence. The Gunning Fog Index focuses on complex words (three or more syllables). Coleman-Liau uses character counts instead of syllables, making it more reliable for technical text with acronyms. The SMOG Index specifically measures the density of polysyllabic words.
Healthcare communication guidelines recommend a 6th-grade reading level for patient-facing materials. Government agencies like the SEC require plain language in public documents. Using multiple readability formulas gives you a more reliable assessment than relying on any single score, since each formula has known biases.
To improve readability: replace multi-syllable words with shorter synonyms, break sentences longer than 25 words, use active voice over passive constructions, and lead with the main point in each paragraph. Even small changes — like replacing 'utilize' with 'use' — can shift a grade level.
How the Readability Checker Works
- Paste your text into the input field
- The tool calculates multiple readability scores (Flesch-Kincaid, Gunning Fog, Coleman-Liau, etc.)
- See the estimated reading grade level for your text
- Get specific suggestions to improve readability
Understanding Readability Scores
The Flesch Reading Ease score ranges from 0 (very difficult) to 100 (very easy) — aim for 60-70 for general audiences. Flesch-Kincaid Grade Level maps directly to US school grade levels. The Gunning Fog Index penalizes complex words (3+ syllables). To improve readability: break long sentences into shorter ones, replace jargon with simpler words, and use active voice instead of passive constructions.
When to Use the Readability Checker
Use this tool whenever you write content for a specific audience and need to verify that the language complexity matches their reading level. It is essential for healthcare communications, government documents, educational materials, marketing copy, and any content where comprehension directly affects outcomes.
Common Use Cases
- •Ensuring patient-facing healthcare documents meet plain language requirements
- •Optimizing marketing copy for maximum comprehension and conversion
- •Verifying that educational materials match the target grade level
- •Analyzing competitor content to match or simplify your writing style Keyword Density Analyzer — SEO Checker
Expert Tips
- ✱Break sentences longer than 25 words into two shorter sentences for an immediate readability improvement.
- ✱Replace multi-syllable words with simpler synonyms: 'use' instead of 'utilize', 'help' instead of 'facilitate'.
- ✱Read your text aloud — if you stumble or run out of breath, the sentence is too complex.
Frequently Asked Questions
- No single score is universally best. Flesch Reading Ease is the most intuitive (higher = easier). Flesch-Kincaid Grade Level maps to US school grades, making it practical for educational content. Gunning Fog penalizes jargon heavily, so it's useful for business writing. Use multiple scores together for the most reliable assessment.
- Most web content should target a 6th to 8th grade reading level (Flesch-Kincaid Grade 6-8, or Flesch Reading Ease 60-70). This makes your content accessible to about 85% of the adult population. Even technical content benefits from simpler language — complex ideas can be explained with simple words.
- Each formula weighs different text features. Flesch-Kincaid focuses on syllables and sentence length. Gunning Fog counts complex words (3+ syllables). Coleman-Liau uses character counts instead of syllables. These different approaches produce varied results, especially for technical text with many short abbreviations or long technical terms.
- Readability formulas are statistical estimates, not exact measurements. They cannot account for context, reader expertise, or text structure beyond sentence and word complexity. A text about quantum physics at grade 8 readability is still harder to understand than a cooking recipe at the same grade level. Use scores as guidelines, not absolute rules.
Which readability score should I use?▾
What reading level should I target for web content?▾
Why do different formulas give different scores?▾
How accurate are readability scores?▾
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