Overview
Analyses text with six published readability formulas — Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog, SMOG, Coleman-Liau and the Automated Readability Index — alongside word, sentence, paragraph, syllable and polysyllable counts and estimated reading and speaking times. Paste a draft and see instantly whether it reads like a magazine or a legal contract — all computed locally.
How It Works
Paste text into the input area. A row of stat tiles fills in immediately: characters, words, sentences, paragraphs, syllables, words with three or more syllables, read time at 200 words per minute and speaking time at 130 words per minute. Below them, a table lists all six readability indices with their scores and a plain-language interpretation: Flesch Reading Ease as its own row (higher is easier), and the five grade-level estimates — Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau and ARI — each translated into an approximate US school grade. Edit and re-paste freely; every statistic recomputes on each change.
Step-by-Step Usage Guide
- Paste the passage you want scored into the input area.
- Read Flesch Reading Ease first: above 60 is plain English, below 50 is difficult for a general audience.
- Compare the five grade-level indices — Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau and ARI — for the US school grade your text demands.
- Use read time (200 wpm) and speak time (130 wpm) to size the piece for its medium, then edit and re-check.
Technical Specifications & Standards
Each index answers the same question with different arithmetic. Flesch Reading Ease (1948) is 206.835 minus 1.015 times words-per-sentence minus 84.6 times syllables-per-word: roughly 100 for very easy text, 60-70 for plain English, below 30 for graduate-level difficulty. Flesch-Kincaid Grade Level is its sibling reworked into a grade scale: 0.39 times words-per-sentence plus 11.8 times syllables-per-word minus 15.59. Gunning Fog estimates years of education as 0.4 times (words-per-sentence plus 100 times the share of words with three or more syllables). SMOG, McLaughlin's 1969 formula, is 3 plus the square root of polysyllabic words times 30 divided by sentences — which is why a passage with no polysyllables floors at grade 3. Coleman-Liau is the outlier that counts characters instead of syllables: 0.0588 times letters per 100 words minus 0.296 times sentences per 100 words minus 15.8. ARI is 4.71 times characters per word plus 0.5 times words per sentence minus 21.43. Every formula stands or falls on the syllable counter, which is a documented heuristic: words of three letters or fewer count as one, a silent final e is dropped (kept when it forms a '-le' ending), trailing '-ed' and '-es' are dropped only when they do not add a spoken syllable ('jumped' and 'makes' lose one, 'wanted', 'boxes' and 'eagles' do not), and remaining vowel groups of a, e, i, o, u and y each count once. That is accurate for most common English words and wrong for irregular spellings, so the panel says so explicitly. Where the formulas disagree — and they will, by a grade or more on the same text — treat the spread itself as information: agreement means the difficulty judgement is robust.
Targeted Use Cases
- Checking that customer-facing copy, policies or documentation hits a plain-English target before publishing.
- Comparing two drafts of the same paragraph to see which is objectively simpler across all six formulas.
- Sizing a script by speaking time at a realistic 130 words per minute.
- Auditing content for accessibility, where high syllable density and long sentences are measurable barriers.
Notes & Gotchas
- Aim for Flesch Reading Ease of 60-70 for general web audiences; legal and technical text will legitimately score lower.
- Shorten sentences first: words-per-sentence moves every formula on the page more than word length does.
- Trust the syllable heuristic less on proper nouns and technical jargon; scores drift when such words dominate.
- When the grade indices disagree by several grades, shorten a sample by hand and re-score rather than averaging them mentally.
- Score representative sections rather than a whole mixed document — averages hide the paragraph readers give up on.
Frequently Asked Questions
What is a good Flesch Reading Ease score?
For general audiences, 60-70 — plain English a mid-teen reader follows comfortably. Reader's Digest scores about 65, academic writing falls below 40. Higher means easier; below 30 is graduate-level difficulty.
What is the difference between Flesch Reading Ease and Flesch-Kincaid Grade Level?
Reading Ease is the 0-100 'higher is easier' scale (206.835 minus sentence-length and syllable-length penalties). Flesch-Kincaid Grade Level reweights the same two inputs into a US school-grade number where higher means harder (0.39 times words-per-sentence plus 11.8 times syllables-per-word minus 15.59). This tool shows both, correctly labelled.
Why do SMOG and the other grade formulas disagree?
They weigh different proxies for difficulty: sentence length, polysyllable density, character counts. A text can be grade 8 by one and grade 12 by another. When the spread is wide, the honest reading is that the text sits at the top of the range for a general audience.
How accurate is the syllable counting?
It is a heuristic: short words count as one syllable, silent endings are stripped and vowel groups are counted. It is reliable for ordinary English prose but miscounts irregular words, names and borrowed terms, which nudges the readability scores; the panel carries a visible caveat saying exactly this.
What reading and speaking speeds are assumed?
Read time divides words by 200 per minute, a common silent-reading average; speaking time divides by 130 per minute, a typical presentation pace. Both round up to the next minute.