Plain Language Checker
Analyze text for readability, grade level, and plain language compliance. Checks Flesch-Kincaid, SMOG, ARI, Coleman-Liau, Gunning Fog scores plus passive voice, complex words, and federal Plain Writing Act guidelines. Free, browser-only, no sign-up required.
Runs entirely in your browser. Your text is never uploaded, stored, or shared. Compliant with Plain Writing Act of 2010 and Federal Plain Language Guidelines.
What This Plain Language Checker Analyzes
Readability Score Reference
| Score | Target | Meaning |
|---|---|---|
| Flesch-Kincaid Grade | ≤ 10 (federal) | U.S. grade level needed to understand |
| Flesch Reading Ease | ≥ 60 (plain) | 0–100 scale, higher = easier |
| SMOG Index | ≤ 10 | Health literacy standard |
| ARI | ≤ 10 | Technical documentation |
| Coleman-Liau | ≤ 10 | Character-based grade level |
| Gunning Fog | ≤ 12 | Business writing standard |
Why Plain Language Matters for Every Document You Write
Whether you are a federal program analyst drafting a benefits letter, a state health department writing Medicaid enrollment instructions, a city clerk posting a building permit notice, or a nonprofit grant writer preparing a community outreach flyer — the rule is the same: if people cannot understand it on the first read, the document has failed. The Plain Writing Act of 2010 made this a legal requirement for U.S. federal agencies, and most state and local governments have adopted similar standards. This free plain language checkergives you an instant, data-driven way to measure readability, spot compliance gaps, and fix problems before your audience ever sees the text.
Unlike generic readability tools, this analyzer is built around the actual guidelines federal agencies use: the Federal Plain Language Guidelines, OMB Memorandum M-11-15, theCDC Clear Communication Index, and Section 508 / WCAG 2.1 Success Criterion 3.1.5. It calculates six readability formulas, flags passive constructions, identifies complex words with plain alternatives, and produces a downloadable report you can attach to your compliance documentation.
Readability Formulas at a Glance
Each formula weighs sentence length and word complexity differently. The table below shows what each measures, the typical target for U.S. government content, and how this tool reports it.
| Formula | What It Measures | Gov Target | Output Here |
|---|---|---|---|
| Flesch–Kincaid Grade Level | Sentence length + syllables per word | ≤ 10 (≤ 8 preferred) | Grade (e.g., 9.2) |
| Flesch Reading Ease | Inverse of grade level (0–100 scale) | ≥ 60 (≥ 70 preferred) | Score + label |
| SMOG Index | Polysyllable count in 30 sentences | ≤ 10 | Grade equivalent |
| Automated Readability Index (ARI) | Characters per word + words per sentence | ≤ 10 | Grade equivalent |
| Coleman–Liau Index | Characters per 100 words + sentences per 100 words | ≤ 10 | Grade equivalent |
| Gunning Fog Index | Words per sentence + % complex words | ≤ 12 | Grade equivalent |
Sources: Federal Plain Language Guidelines (plainlanguage.gov), OMB M-11-15, CDC Clear Communication Index, NIH Plain Language Initiative.
Federal Plain Language Checklist (Quick Audit)
Use this checklist alongside the tool's automated analysis. The checker covers the measurable criteria; you verify the rest manually.
- ✓Average sentence length ≤ 20 words — Tool flags if over 20.
- ✓Flesch–Kincaid Grade ≤ 10 — Tool shows exact grade level.
- ✓Flesch Reading Ease ≥ 60 — Tool shows score + label.
- ✓No passive voice (or minimal) — Tool counts instances.
- ✓Complex words replaced — Tool lists 3+ syllable words with alternatives.
- ☐Active voice throughout — Manual check: "Who does what to whom?"
- ☐Pronouns used (you, we) — Manual check for direct address.
- ☐Vertical lists for complex steps — Manual check.
- ☐Descriptive headings — Manual check.
- ☐Definitions for technical terms — Manual check.
Green = automated by this tool. Blue = manual verification needed.
Real-World Scenarios: Who Uses This Daily
Federal Agency Program Analyst
Drafts SNAP benefit letters, Medicare notices, VA disability letters. Must meet Plain Writing Act, OMB M-11-15, and agency style guide. Runs every draft through this checker before supervisor review. Downloads report for compliance file.
State Health Department Writer
Creates Medicaid enrollment guides, vaccine info sheets, WIC program flyers. State law mirrors federal Plain Writing Act. Uses SMOG and Flesch scores to hit grade 8 target for low-literacy populations. Checks CDC Clear Communication Index language criteria.
City Clerk / Municipal Communications
Posts building permit instructions, zoning hearing notices, utility shutoff warnings. Residents include non-native English speakers and seniors. Targets Flesch Reading Ease 70+. Flags passive voice in legal boilerplate ("The permit must be obtained" → "You must get the permit").
Legal Aid / Nonprofit Grant Writer
Writes intake forms, know-your-rights guides, grant reports. Funders increasingly require plain language. Uses complex-word finder to swap legalese ("pursuant to" → "under," "heretofore" → "until now"). Ensures WCAG 3.1.5 reading level compliance for web publication.
Healthcare Compliance Officer
Reviews patient consent forms, HIPAA notices, discharge instructions. State laws (CA, TX, NY) mandate specific readability scores for consent forms. Runs every revision through checker; attaches score report to compliance binder for audits.
Insurance / Financial Services Writer
Prepares policy summaries, disclosure notices, fee schedules. NAIC model regulations and state insurance codes often require Flesch score 40+ or grade 12 max. Uses tool to prove compliance before filing with state DOI.
The Formulas Behind the Scores (For the Curious)
Google and compliance auditors love transparency. Here are the exact equations this tool implements — so you can cite them in your documentation.
Flesch–Kincaid Grade Level
0.39 × (words / sentences) + 11.8 × (syllables / words) − 15.59
Developed for the U.S. Navy in 1975. Adopted by DoD, EPA, IRS, and most state governments as the primary grade-level metric.
Flesch Reading Ease
206.835 − 1.015 × (words / sentences) − 84.6 × (syllables / words)
0–100 scale. Higher = easier. 60–70 = standard (8th–9th grade). 70–80 = fairly easy. 90+ = very easy (5th grade).
SMOG Index (Simple Measure of Gobbledygook)
1.043 × √(30 × complexWords / sentences) + 3.1291
Counts words with 3+ syllables in 30-sentence samples. Preferred for health materials (NIH, CDC). More conservative than Flesch–Kincaid.
Automated Readability Index (ARI)
4.71 × (characters / words) + 0.5 × (words / sentences) − 21.43
Uses character count instead of syllables — faster to compute, no syllable dictionary needed. Originally for real-time typewriter monitoring.
Coleman–Liau Index
0.0588 × (characters / words × 100) − 0.296 × (sentences / words × 100) − 15.8
Also character-based. Designed for computer scoring without syllable counting. Used in early word processors.
Gunning Fog Index
0.4 × [(words / sentences) + 100 × (complexWords / words)]
Heavy weight on "foggy" words (3+ syllables). Popular in business and legal writing assessment. Target ≤ 12 for general audiences.
Related Text Tools on NexoText
Once your plain language analysis is done, these complementary tools help you finish the job:
Readability Checker — Deeper structural analysis: sentence length distribution, paragraph complexity, reading time, speaking time, and Flesch/Kincaid/SMOG/ARI/Coleman-Liau/Gunning Fog in a dashboard view.
Word Counter — Real-time word, character, sentence, paragraph counts plus keyword density and reading level. Essential for meeting strict word limits on federal forms (SF-424, Grant.gov, etc.).
Sentence Counter — Breaks down sentence count, average length, and long-sentence flagging. Pairs perfectly with this checker's "sentences over 20 words" alerts.
Inclusive Language Checker — Flags biased, outdated, or exclusionary terms. Federal style guides (GPO, NIH, CDC) require inclusive language alongside plain language. Run both before publishing.
Passive to Active Voice Converter — This checker flags passive voice; that tool rewrites it. Paste a flagged sentence and get an active-voice alternative instantly.
Text Case Converter — Federal headings often require Title Case or Sentence case. Convert entire documents in one click (UPPERCASE, lowercase, Title Case, Sentence case, camelCase, snake_case, kebab-case).
Remove Special Characters — Strips smart quotes, em dashes, non-breaking spaces, and other Word/PDF artifacts that break plain text processing and accessibility screen readers.
APA & MLA Citation Generator — For research-backed government reports. Generates properly formatted references so your citations don't undermine the plain language in your narrative.
A Clear Sentence Is a Civic Act
The Plain Writing Act was not passed to make writers' lives harder. It was passed because a veteran in rural Montana could not understand his VA benefits letter. Because a single mother in Houston missed a Medicaid renewal deadline because the notice was written at a 14th-grade level. Because a small business owner in Ohio gave up on a federal grant application after reading the same paragraph three times.
Every time you run a document through this checker and lower the grade level by one point, you make it accessible to roughly 5 million more American adults. That is not a metaphor — that is the National Assessment of Adult Literacy data.
Paste your text above. Hit Analyze. Fix what the tool flags. Publish with confidence that your words will reach the people they are meant to serve.
Frequently Asked Questions
What is the Plain Writing Act of 2010?
The Plain Writing Act of 2010 (Public Law 111-274) requires U.S. federal agencies to write clear, concise, well-organized documents that the public can understand and use. It applies to letters, publications, forms, notices, and instructions related to federal benefits, services, or compliance requirements. Agencies must train employees, establish oversight processes, and maintain a plain writing section on their websites.
What readability formulas does this tool calculate?
This plain language checker calculates six industry-standard readability metrics: Flesch-Kincaid Grade Level, Flesch Reading Ease, SMOG Index, Automated Readability Index (ARI), Coleman-Liau Index, and Gunning Fog Index. Each uses a different formula weighting sentence length, word length, and syllable count to estimate the U.S. grade level needed to comprehend the text.
What Flesch-Kincaid grade level should government content target?
Federal plain language guidelines recommend a Flesch-Kincaid Grade Level of 10 or lower for public-facing documents. For general audiences, grade 8 or below is ideal. The Plain Writing Act and OMB Memorandum M-11-15 direct agencies to write at a level appropriate for the intended audience, typically no higher than 10th grade for general public communications.
How does the passive voice detector work?
The tool scans for common passive constructions using patterns like "be verb + past participle" (e.g., "was reviewed," "has been completed") and "get verb + past participle" (e.g., "got approved"). It flags potential instances so you can rewrite them in active voice — for example, changing "The application was submitted by the applicant" to "The applicant submitted the application."
What counts as a complex word in plain language analysis?
Words with three or more syllables are flagged as complex. The tool identifies these and suggests simpler alternatives from the Federal Plain Language Guidelines word list — for example, "utilize" becomes "use," "facilitate" becomes "help," and "implement" becomes "carry out." Reducing complex words directly improves Flesch Reading Ease and lowers grade level scores.
Is my text uploaded or stored when I use this checker?
No. This plain language checker runs entirely in your browser using JavaScript. Your text never leaves your device, is never sent to a server, and is never stored. It works offline once the page loads. This makes it safe for sensitive government, legal, healthcare, or financial documents.
Can this tool check compliance with CDC Clear Communication Index?
Yes. The CDC Clear Communication Index evaluates materials on seven criteria including main message, call to action, language, and design. This checker covers the language criteria — readability scores, passive voice, complex words, sentence length, and grade level — which are core Index components. For full Index scoring, you would also need to evaluate behavioral recommendations and design elements manually.
What is a good Flesch Reading Ease score for government writing?
A score of 60 or higher (equivalent to 8th–9th grade reading level) is recommended for public-facing government content. Scores 70–80 are "fairly easy" (7th grade), 80–90 are "easy" (6th grade), and 90+ are "very easy" (5th grade). Most federal agency style guides target 60–70 for general audiences. Scores below 50 indicate difficult text that many adults will struggle to understand.
Does this work for Section 508 and WCAG compliance?
Plain language is a Section 508 and WCAG 2.1 requirement (Success Criterion 3.1.5: Reading Level). This tool helps you meet the "reading level" provision by measuring grade level and identifying barriers like passive voice and jargon. However, full 508/WCAG compliance also requires proper heading structure, alt text, color contrast, keyboard navigation, and other technical accessibility factors this tool does not assess.
Can I use this for legal contracts or medical consent forms?
Yes. Legal and medical documents are notorious for low readability. Many states now require consumer contracts, insurance policies, and informed consent forms to meet specific readability standards (often Flesch score 40+ or grade 12 max). This checker helps you measure and improve those documents. Always have legal counsel review final language for accuracy.
How do I fix a high grade level score?
Three quick wins: (1) Shorten sentences — aim for 15–20 words average. (2) Replace 3+ syllable words with 1–2 syllable alternatives ("commence" → "start," "terminate" → "end"). (3) Convert passive to active voice ("was approved by" → "approved"). Each change reduces grade level by 0.5–2 points. Re-check after editing to confirm improvement.