Readability Score Checker
Calculate Flesch-Kincaid, Gunning Fog, Coleman-Liau and reading ease scores with colour-coded ratings and text statistics
Paste text to see readability analysis
Check how easy your text is to read with multiple readability metrics.
The Four Scores This Tool Calculates
Paste text and the tool computes Flesch Reading Ease (0 to 100), Flesch-Kincaid Grade Level (US school grade), Gunning Fog Index (years of education), and Coleman-Liau Index (also a grade level, but built from character counts not syllables). Below the scores it shows the underlying stats: word count, sentence count, syllable count, average words per sentence, and average syllables per word. Each score gets a colour-coded label - green for easy, yellow for standard, orange for advanced, red for very advanced.
Four scores instead of one because each formula weights things differently. Flesch Reading Ease and Flesch-Kincaid are the dominant choices for general writing because they balance sentence length and syllable count. Gunning Fog penalises words of three or more syllables harder, which makes it sensitive to jargon. Coleman-Liau ignores syllables entirely and works only from characters and sentences, which makes it the most reliable score on text where automatic syllable counting fails (acronyms, technical abbreviations, proper nouns).
What 'Standard' Means and What to Aim For
On the Flesch Reading Ease scale, 60 to 70 is 'Standard' - readable by an average 13- to 15-year-old. Below 30 is 'Very Difficult' and is academic-paper territory; above 90 is 'Very Easy' and reads like a children's book. For the grade-level scores (Flesch-Kincaid, Gunning Fog, Coleman-Liau), the colour coding here flags 0 to 6 as easy, 7 to 9 as standard, 10 to 12 as advanced, 13+ as very advanced. Most online writing should target Flesch Reading Ease 60-70 and grade level 7-9.
If you write for a B2C audience and your scores come back grade 14, your sentences are too long or your words are too polysyllabic. The 'Average words per sentence' stat will tell you which: above 20 means cut your sentences; above 1.7 average syllables per word means swap long words for short ones. A worked example: a paragraph with 92 words, 3 sentences, average 30.7 words per sentence and 1.9 syllables per word will score around grade 18. Break those three sentences into seven, replace 'utilise' with 'use' and 'subsequently' with 'then', and the same content will read at grade 9.
Differences Between This and the Sister Tool
This tool focuses on four core formulas with side-by-side stats and colour rating. The [readability checker](/readability-checker) adds a fifth formula (SMOG), an averaged grade level across all four formulas, an estimated reading time at 200 words per minute, and an automatic improvement-tips panel. If you want a quick check with raw numbers and stats, use this one. If you want a full assessment with an automatic verdict and suggestions, use the other.
Both tools use the same underlying formulas (originals, not modified) so the numbers will match within rounding. The choice is presentation: this tool exposes the inputs (syllable count, character count, average sentence length) so you can see what is driving each score. The other tool focuses on outputs (verdict, reading time, tips) so you can act faster. Pair this with the [word counter](/word-counter) if you also need section-by-section word counts.
Frequently Asked Questions
Why are SMOG scores missing from this tool?
This tool focuses on the four most-cited formulas: Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, and Coleman-Liau. SMOG is included in the [readability checker](/readability-checker) instead. SMOG is most useful for technical and medical writing where polysyllabic words are common; for general prose the four formulas here cover the same ground.
Why might Flesch-Kincaid and Coleman-Liau give different grade levels for the same text?
Because they measure different things. Flesch-Kincaid uses syllables per word; Coleman-Liau uses characters per word. A text full of long but simple words ('representative', 'organisation', 'environment') reads as harder by Flesch-Kincaid (high syllable count) but only moderately hard by Coleman-Liau (long characters but not unusually so). A 2-grade gap between the two scores is normal; a 5-grade gap usually means automatic syllable detection has failed on some unusual words.
Does this work on languages other than English?
No. All four formulas were calibrated on English text and use English syllable rules and English character frequencies. Running them on French, German, or Spanish gives nonsense scores because syllable structure and average word length differ substantially. Use a language-specific readability tool for non-English text.
How long does my text need to be for accurate scores?
At least 100 words, ideally 300+. Below 100 words a single long sentence or one polysyllabic word can swing the score by 2 to 3 grade levels. Below 30 words the scores are essentially noise. Marketing copy is often shorter than this threshold; in that case judge it by the underlying stats (average sentence length, syllables per word) rather than the composite scores.