Readability Checker Widget
Embed a readability checker in your writing or plain-language guide. Readers paste English text and get six standard readability scores with what they mean, plus the word, sentence and syllable counts behind them.
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Exactly what your visitors will seeUnder the widget on your page: Powered by A2Z Tools
Embed code
<iframe src="https://a2z.tools/embed/w/readability-checker" title="Readability Checker by A2Z Tools" width="100%" height="930" style="border:0;width:100%" loading="lazy" allow="clipboard-write"></iframe>
A plain iframe. Works everywhere, including site builders that strip scripts. Adjust height if your content needs more room.
<div data-a2z-widget="readability-checker" data-height="930"></div> <script async src="https://a2z.tools/embed.js"></script>
Adds a small script (what it does) that sizes the widget to fit its content, loads it lazily and keeps it isolated from your page's CSS.
Works with
How it works
Every score comes from a published formula applied to counts of words, sentences, syllables, letters and complex words, using the same text engine as the A2Z Readability Score Analyzer. Flesch Reading Ease runs from about 0 (very hard) to 100 (very easy); the grade-level formulas estimate the US school grade needed to follow the text. Syllables are counted with an English heuristic, so scores that depend on them are estimates; SMOG was designed for samples of 30 sentences or more and is marked unreliable below that. The formulas were built for English and are not meaningful for other languages.
Method
- Flesch Reading Ease = 206.835 - 1.015 (words / sentences) - 84.6 (syllables / words)
- Flesch-Kincaid Grade = 0.39 (words / sentences) + 11.8 (syllables / words) - 15.59
- Gunning Fog = 0.4 [(words / sentences) + 100 (complex words / words)]
- SMOG = 1.0430 sqrt(polysyllables x 30 / sentences) + 3.1291
- Coleman-Liau = 0.0588 L - 0.296 S - 15.8 (L letters, S sentences per 100 words)
- ARI = 4.71 (characters / words) + 0.5 (words / sentences) - 21.43
- Complex/polysyllabic word = 3 or more estimated syllables (Fog also excludes hyphenated compounds, capitalised words mid-sentence and syllables added by -es, -ed or -ing); scores shown to one decimal
Limitations
- Syllables are counted by an English spelling heuristic, not a dictionary, so words such as "business" or "naive" can be off by one syllable.
- Formulas see only word and sentence length; they cannot judge jargon, logic, layout or whether the reader knows the topic.
- Bullet lists, headings without full stops and code make sentence counts unreliable; score continuous prose only.
- No formula for other languages (such as Amstad for German or Fernandez Huerta for Spanish) is included.
Where publishers use it
- Plain-language guides for government and healthcare writers
- Content-marketing blogs aiming at a general audience
- Teachers matching texts to students' reading levels
- UX-writing style guides for interface and help text
Questions
What is a good Flesch Reading Ease score?
60-70 is plain English that most adults read easily. Many public-sector guides aim for 60 or higher; academic writing often scores below 30.
Why do the grade levels disagree?
Each formula weighs different things - syllables, letters or long words - so they differ by a grade or two. Look at the overall picture.
Does it work for other languages?
No. The formulas and the syllable counter are designed for English.
How much text do I need?
At least 100 words for stable results, and 30 sentences for SMOG.
Sources
- Flesch, R. (1948). A new readability yardstick. Journal of Applied Psychology 32(3), 221-233 - American Psychological Association . Reading Ease formula
- Kincaid, J. P., Fishburne, R. P., Rogers, R. L. & Chissom, B. S. (1975). Derivation of new readability formulas for Navy enlisted personnel. Research Branch Report 8-75 - Naval Technical Training Command (DTIC ADA006655) . Flesch-Kincaid Grade Level
- Gunning, R. (1952). The Technique of Clear Writing - McGraw-Hill (Internet Archive copy) . Fog Index
- McLaughlin, G. H. (1969). SMOG grading - a new readability formula. Journal of Reading 12(8), 639-646 - ERIC EJ004016 . SMOG and its 30-sentence sample
- Coleman, M. & Liau, T. L. (1975). A computer readability formula designed for machine scoring. Journal of Applied Psychology 60(2), 283-284 - American Psychological Association . Coleman-Liau Index
- Smith, E. A. & Senter, R. J. (1967). Automated Readability Index. AMRL-TR-66-220 - Aerospace Medical Research Laboratories (DTIC AD0667273) . ARI
Cite or recommend this tool
If you reference this tool in an article, course or documentation, these formats are ready to copy. They are optional - nothing is added to your site unless you paste it.
A2Z Tools Readability Checker https://a2z.tools/readability-score-analyzer
<a href="https://a2z.tools/readability-score-analyzer">A2Z Tools Readability Checker</a>
[A2Z Tools Readability Checker](https://a2z.tools/readability-score-analyzer)
Readability Checker by A2Z Tools - https://a2z.tools/readability-score-analyzer
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