Readability Score
SEO Tools
Score your content's reading difficulty with six classic readability formulas. Flesch, Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, and Automated Readability — live as you type.
Runs entirely in your browserAbout Readability Score
Readability scores measure how hard your content is to read by counting sentence and word complexity. They were developed for the US military, newsroom editors, and education researchers across the 20th century, and they're still the standard quick-check for content quality. Modern content tools (Yoast, Hemingway, Grammarly) all expose one or more of these scores because they correlate well with bounce rate and reader engagement — pages that are too dense for the audience get abandoned.
This tool computes six scores in parallel. Flesch Reading Ease gives a 0–100 score (higher = easier). The others — Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau, and Automated Readability Index — return US school grade levels. Different formulas weight different things (Flesch family weights syllables; Coleman-Liau weights letter count; SMOG was designed for medical content), so checking multiple gives a robust picture. For general consumer content, aim for grade 7–9 (Flesch 60–70). Technical writing usually runs grade 11+; that's fine — match the level to your audience. All computation is local in your browser.
How to use
- 1
Paste your content
Drop a paragraph, article, blog post, or product description into the editor. Scores update live.
- 2
Read the six scores
Each row shows the score and a one-line interpretation. Lower grade level = easier to read. Flesch Reading Ease is the exception (higher = easier).
- 3
Check the stats panel
Raw inputs to the formulas: words, sentences, syllables, complex words, average words per sentence. Useful for spot-checking obvious issues like a 60-word sentence skewing the score.
- 4
Iterate
Common moves: split long sentences (high avg words/sentence is the #1 readability killer), swap multi-syllable words for shorter synonyms, use active voice. Watch the scores improve.
Examples
Simple consumer copy
Input
Free Tools Grid runs in your browser. No sign-up. No upload. No cost.Output
Flesch Reading Ease ≈ 96 (Very easy, ~grade 4–5). Flesch-Kincaid grade ≈ 1.5.Dense academic prose
Input
The proliferation of interconnected computational artifacts necessitates the implementation of robust cryptographic primitives to mitigate adversarial exploitation.Output
Flesch Reading Ease ≈ 5 (Very difficult). Gunning Fog ≈ 22.Frequently asked questions
Which score should I prioritize?+
For most use cases, Flesch Reading Ease and Flesch-Kincaid Grade are the standard pair (one is the 0–100 inverse of the other). Use SMOG when your content is health/medical. Use Coleman-Liau when your text has lots of acronyms or numbers (it doesn't count syllables). For most writers, just keep an eye on Flesch Reading Ease — 60+ is fine for general audiences.
What grade level should I target?+
General consumer content: grade 7–9 (Flesch 60–70). News writing: grade 6–8. Technical documentation: grade 10–12 is fine if the audience is technical. Academic papers: grade 14+ is acceptable but should still be tight. Marketing copy: grade 5–7 for broadest appeal.
Why do the scores differ from each other?+
Each formula weighs inputs differently. Flesch weights syllables; Coleman-Liau weights letter count; SMOG weights complex (3+ syllable) words. They usually agree directionally but can differ by 1–2 grades on the same text. Median across all six is a robust signal.
Why does my content score lower than I expect?+
Usually one of: (1) sentences are too long — break them up; (2) you're using long words where short ones would work; (3) passive voice is dragging the score down; (4) too many proper nouns or jargon (these count as complex words). The stats panel surfaces the raw culprits.
Are readability scores a Google ranking factor?+
Not directly. Google has explicitly said readability is not a direct signal. But high-readability content correlates with longer dwell time and lower bounce rate, both of which Google can measure and may weigh. Aim for clarity for your readers; the SEO benefit follows.
Is my text sent anywhere?+
No. All computation runs in your browser using pure JavaScript. Nothing leaves your device.
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