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.

SEO & Content Tool Runs in your browser Free · no ads

Customize your widget

Theme
Auto follows the visitor's light/dark setting.
Style
Attribution on your page
The widget is free; a visible credit is how you can say thanks. It is one plain line, shown in the code below, linking to the tool with rel="nofollow". Switch it off here or delete the line - the widget works the same either way.
More options
Starting values
Leave blank to use the widget's defaults. Visitors can still change every value.

Live preview

Exactly what your visitors will see

Under the widget on your page: Readability Checker by A2Z Tools

Embed code

<div data-a2z-widget="readability-checker" data-height="930"></div>
<p class="a2z-attribution" style="margin:6px 0 0;font:12px/1.4 system-ui,sans-serif;opacity:.8">Readability Checker by <a href="https://a2z.tools/readability-score-analyzer" target="_blank" rel="nofollow noopener">A2Z Tools</a></p>
<script async src="https://a2z.tools/embed.js"></script>

Recommended. A small script (what it does) sizes the widget to fit its content, loads it lazily and keeps it isolated in its own frame. Works in WordPress (Custom HTML block), Squarespace, Webflow, Shopify, Blogger, React / Next.js and plain HTML - anywhere a <script> tag is allowed.

Works with

Advertisement

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

  1. Flesch, R. (1948). A new readability yardstick. Journal of Applied Psychology 32(3), 221-233 - American Psychological Association . Reading Ease formula
  2. 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
  3. Gunning, R. (1952). The Technique of Clear Writing - McGraw-Hill (Internet Archive copy) . Fog Index
  4. 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
  5. 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
  6. 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

Related widgets

More SEO & Content widgets →

  • Word Counter

    SEO & Content Tool

    Words, characters, sentences, paragraphs, reading time and social-media character limits.

    Get code

  • Reading Time Calculator

    SEO & Content Calculator

    Reading and speaking time for a word count or pasted text, at research-based reading speeds.

    Get code

  • Keyword Density Checker

    SEO & Content Tool

    Top one-, two- and three-word phrases in a text with counts and density, plus a focus keyword.

    Get code

  • SERP Snippet Preview

    SEO & Content Tool

    Preview a title, URL and meta description as a Google-style result, with pixel-width estimates.

    Get code

  • Social Card Preview

    SEO & Content Tool

    Preview Facebook, LinkedIn and X link cards and generate the Open Graph meta tags.

    Get code

  • URL Slug Generator

    SEO & Content Generator

    Turn a title into a clean URL slug: accents transliterated, optional stop-word removal and length cap.

    Get code

Preview

CustomizeGet code
A2Z EMBEDS FOR YOUR WEBSITE
Advertisement