Readability Score Calculator

Calculate multiple readability scores for any text — Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog Index, and SMOG Index.

What Does This Tool Do?

Readability scores measure how difficult a piece of writing is to understand. They consider factors like sentence length and word complexity to estimate the education level a reader needs to understand the text. This tool calculates four of the most widely used readability formulas simultaneously.

Key Features

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4 Readability Formulas

Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog, and SMOG Index.

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Grade Level

Shows the US school grade level required to read your text.

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Text Statistics

Also shows word count, sentence count, syllables, and average sentence length.

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Instant

All scores calculated simultaneously with one click.

How to Use This Tool

Paste your text (at least a paragraph — more text gives more accurate scores).
Click Analyze to calculate all readability scores.
Review the scores and grade levels.
If scores are too high, simplify by shortening sentences and using simpler words.

How It Works

The text is analyzed for word count, sentence count (by end-punctuation), and syllable count (by vowel groupings with adjustments). Each formula applies its specific weights: Flesch Reading Ease uses sentence and syllable averages, Flesch-Kincaid Grade Level weights them differently, Gunning Fog counts complex (3+ syllable) words, and SMOG uses complex word density.

Common Use Cases

💡 Content Marketing

Aim for Flesch Reading Ease above 60 (7th-9th grade) for blog posts and marketing copy.

💡 Academic Writing

Check that technical papers are appropriately complex for their academic audience.

💡 Medical & Legal

Ensure patient education materials and consumer disclosures are readable by general audiences.

💡 SEO Content

Google favors readable content — aim for clear, concise writing that scores well.

Frequently Asked Questions

What Flesch Reading Ease score should I aim for?

For general online content: 60-70 (8th-9th grade). For marketing copy: 70-80. For academic work: 30-50. Lower scores = harder to read.

Why do different formulas give different grade levels?

Each formula was developed with different text corpora and weights different factors. Flesch-Kincaid and SMOG tend to be most accurate for contemporary texts. Gunning Fog is better for business writing.

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