# Readability Score Calculator

> Free readability score calculator. Check Flesch Reading Ease, Flesch-Kincaid grade, Gunning Fog, SMOG, Coleman-Liau, and ARI for any text in seconds.

**URL:** https://calculators.im/readability-calculator  
**Category:** general  
**Last updated:** 2026-07-03  

Paste any text and instantly get all 5 industry-standard readability scores: Flesch Reading Ease (0-100), Flesch-Kincaid Grade, Gunning Fog Index, SMOG Index, Coleman-Liau Index, and Automated Readability Index (ARI). Free readability score calculator for bloggers, content marketers, SEOs, educators, and copywriters.

Our readability calculator runs all five major readability formulas on any text you paste — no signup, no ads in the analysis flow, no character limit on the input. Get the Flesch Reading Ease score (0-100, higher = easier), Flesch-Kincaid US grade level, Gunning Fog Index (years of formal education needed), SMOG Index (100% comprehension level), Coleman-Liau Index, and Automated Readability Index (ARI). Plus underlying text statistics: word count, sentence count, syllable count, complex word count, and average sentence length. Built for content marketers targeting 7th-8th grade reading level, SEO writers optimizing for accessibility, educators assessing text complexity, and copywriters fine-tuning marketing copy.

## Formula

```
Flesch Reading Ease = 206.835 − 1.015(words/sentences) − 84.6(syllables/words)
```

**Variables:**

- **words/sentences** — Average sentence length — shorter sentences = higher (easier) score
- **syllables/words** — Average syllables per word — shorter words = higher (easier) score
- **Flesch Reading Ease** — 0-100 scale: 90+ very easy (5th grade), 60-70 standard (8th-9th grade), <30 very difficult (college)
- **Flesch-Kincaid Grade** — US school grade level: 0.39(words/sentences) + 11.8(syllables/words) − 15.59

All five readability formulas use the same two underlying signals: sentence length (longer sentences = harder) and word complexity (more syllables per word = harder). They differ in how they weight and combine these signals, and in how the output is scaled. Flesch Reading Ease gives a 0-100 score (higher = easier). Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, and ARI all output a US grade level (8 = 8th grade, 12 = high school senior, 16 = college senior). Most content marketers target an 8th-grade level — the average US adult reading level.

## Worked Example

### Example: A Standard Marketing Paragraph

Short sentences (avg 5.5 words) and simple vocabulary (1.3 syllables/word average) put this text at a 5th-6th grade reading level — very easy. Flesch Reading Ease 79.3 puts it in the 'Fairly Easy' band. Compare to academic writing which typically scores 30-50 on Flesch Reading Ease and grade level 12-16.

## How to Check Your Content Readability Score in 3 Steps

1. **Paste Your Text** — Drop any English text into the textarea — blog post, article, marketing copy, document. No character limit and no signup required.
2. **Read All 5 Scores Live** — Flesch Reading Ease (0-100), Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau, and ARI update in real-time as you type or edit.
3. **Compare Average Grade to Target** — For SEO content target grade 7-8. For B2B target grade 9-10. For academic target 14+. Adjust your text until the average grade hits your target.
4. **Optimize and Re-Test** — Shorten sentences, replace 3+ syllable words with simpler synonyms, use active voice. Re-paste the edited text to see the new score instantly.

## Pro Tips

- Most content marketers target a 7th-8th grade reading level — the average US adult reading level per the National Assessment of Adult Literacy
- Flesch Reading Ease scores: 90-100 very easy (5th grade), 80-90 easy (6th grade), 70-80 fairly easy (7th grade), 60-70 plain English (8th-9th), 50-60 fairly difficult (10th-12th), 30-50 difficult (college), 0-30 very difficult (postgraduate)
- Shorter sentences are the single biggest lever for improving readability — try to keep average sentence length under 20 words
- Replace complex words (3+ syllables) with simpler synonyms — 'use' instead of 'utilize', 'help' instead of 'facilitate', 'show' instead of 'demonstrate'
- SEO research shows easier-to-read content ranks better — Yoast and SurferSEO both flag content above 9th-grade level as a concern
- Different formulas give different scores for the same text — that's normal. Use the AVERAGE of all 5 (output as 'Average Grade') as your target metric
- Hemingway-style writing (simple words, short sentences, active voice) typically scores 5-7 on grade level — that's the gold standard for digital content
- Academic writing isn't graded on readability — it's expected to be at grade level 14-18. Don't 'optimize' academic papers down to 8th grade
- Readability scores are LANGUAGE-AGNOSTIC FORMULAS — they work on any English text but don't transfer to other languages without adjustment
- If your readability score seems wrong, check syllable counting — heuristic syllable counters miss compound words and unusual proper nouns by 5-10%

## Frequently Asked Questions

### What is a readability score?

A readability score is a numerical estimate of how easy or difficult a text is to read. The most common scores output a US school grade level (e.g. 8 = 8th grade, meaning a typical 13-year-old can read it). Others, like Flesch Reading Ease, output a 0-100 score where higher means easier. Scores are calculated from sentence length and word complexity — the two strongest predictors of reading difficulty. Our readability score calculator runs all 5 industry-standard formulas on any text you paste.

### How do I check the readability score of my text?

Paste your text into the textarea above. The readability checker runs all 5 formulas in real-time as you type: Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau, and Automated Readability Index. Underlying counts (words, sentences, syllables, complex words) are also shown. No signup, no character limit, no ads in the analysis flow. The score updates instantly so you can edit and re-test until you hit your target reading level.

### What is a good Flesch Reading Ease score?

For digital content targeting a general audience, aim for 60-70 — the 'Plain English' band where average US adults read comfortably. For marketing copy and social media, push higher (70-80) for maximum accessibility. For technical documentation aimed at industry professionals, 50-60 is acceptable. For academic content, 30-50 is normal. Scores below 30 ('Very Confusing') indicate prose that's too dense for most adult readers — consider breaking up long sentences and replacing jargon.

### Does readability affect SEO?

Indirectly, yes. Google's algorithms don't directly score 'readability' — but they DO measure engagement signals (dwell time, bounce rate, return visits) that correlate strongly with readability. SEO research from Backlinko, Yoast, and SurferSEO shows top-ranking content typically reads at 7th-9th grade level. Why: a typical user wants to scan and extract information quickly. Easier-reading content gets read fully, shared more, linked to more, and ranks better as a result. Our SEO readability checker uses the same Flesch-Kincaid formula Yoast highlights in its WordPress plugin.

### What is the Flesch-Kincaid Grade Level?

Flesch-Kincaid Grade Level converts readability into a US school grade. Formula: 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59. A score of 8.0 means an 8th-grader can read it. The US Department of Defense, IRS, and many state governments use Flesch-Kincaid to ensure public documents are accessible — most target grade 8 or below. Our Flesch-Kincaid calculator outputs this grade alongside the other 4 formulas so you can compare.

### How is the Gunning Fog Index calculated?

Gunning Fog Index = 0.4 × [ (words / sentences) + 100 × (complex words / total words) ]. 'Complex words' = words with 3+ syllables, EXCEPT common suffixes like -ing, -ed, -es and proper nouns. The output is the number of YEARS OF FORMAL EDUCATION a reader needs to understand the text on first reading. 8 = 8th grade. 12 = high school senior. 16 = college senior. 20 = postgraduate. Robert Gunning developed it in 1952 specifically for business writing — most US business publications target 11-13.

### What is the SMOG Index?

SMOG (Simple Measure of Gobbledygook) Index = 1.0430 × √(complex words × 30 / sentences) + 3.1291. Developed by G. Harry McLaughlin in 1969 specifically for the healthcare industry, SMOG is the formula of choice for assessing medical and government documents. It predicts the grade level needed for 100% COMPREHENSION (vs other formulas predicting 75% comprehension). The CDC, NIH, and most US public health agencies target SMOG ≤ 8 for patient-facing content. Our SMOG index calculator outputs this alongside the other 4 formulas.

### What is the Coleman-Liau Index?

Coleman-Liau Index = 0.0588 × L − 0.296 × S − 15.8, where L = average letters per 100 words and S = average sentences per 100 words. Unlike Flesch-Kincaid/Gunning Fog/SMOG which count syllables, Coleman-Liau counts CHARACTERS — making it more reliable for computer-generated scoring (syllable counting is heuristic and imperfect). Output is a US grade level. Developed in 1975 by Meri Coleman and T.L. Liau, often used in word processors and educational software where syllable-based formulas are hard to implement.

### What is the Automated Readability Index (ARI)?

Automated Readability Index = 4.71 × (characters / words) + 0.5 × (words / sentences) − 21.43. Like Coleman-Liau, ARI counts characters rather than syllables — easier to automate, less error-prone. Output is a US grade level (1 = 1st grade, 12 = 12th grade, 14 = college sophomore). Developed in 1967 by Senter and Smith for the US Air Force, originally to assess technical manuals. Most computer-aided readability tools default to ARI when syllable parsing is expensive or unreliable.

### What reading level should blog content target?

For general consumer blogs, target Flesch-Kincaid Grade 7-8 (Flesch Reading Ease 65-75). This matches the average US adult reading level and is the sweet spot for engagement + SEO. For technical / B2B content, grade 9-10 is acceptable but don't go above 12. For academic content, grade 14-18 is appropriate. For social media and email marketing, push down to grade 5-6 for maximum reach. Hemingway-style writing (Hemingway novels score 4-5) is the gold standard for digital content — short sentences, simple words, active voice.

### How can I improve readability?

Six concrete strategies, ordered by impact. (1) SHORTEN SENTENCES — target 15-20 words max. Every sentence over 30 words should be split. (2) REPLACE COMPLEX WORDS with simpler synonyms — 'use' instead of 'utilize', 'show' instead of 'demonstrate', 'help' instead of 'facilitate'. (3) USE ACTIVE VOICE — 'the team shipped the feature' beats 'the feature was shipped by the team'. (4) ADD MORE PARAGRAPH BREAKS — walls of text feel harder regardless of actual readability. (5) REMOVE FILLER WORDS — 'in order to' → 'to', 'due to the fact that' → 'because'. (6) READ ALOUD — if you stumble while reading, the text is too dense.

### Why do different readability formulas give different scores?

Each formula weights sentence length and word complexity differently, and they use slightly different definitions of 'complex word'. Flesch-Kincaid uses syllable count. Coleman-Liau and ARI use character count. Gunning Fog and SMOG use 3+-syllable words but exclude common suffixes. The differences are usually small (1-2 grade levels) for typical content, but can be larger for unusual text (technical writing with long technical terms, or marketing copy with brand names). Our text readability analyzer reports an AVERAGE of all 5 — the most reliable single metric.

### How accurate are readability calculators?

Mathematically, readability calculators are deterministic — given the same text and the same formula, every tool returns the same score. The accuracy gap is in SYLLABLE COUNTING (Flesch, Gunning Fog, SMOG depend on it). Heuristic syllable counters (used by most free tools, including ours) are accurate to within 5% on standard English prose. They struggle with: technical terms, proper nouns, compound words, hyphenated words, and made-up jargon. Coleman-Liau and ARI sidestep this by counting characters instead — they're more reliable for automated scoring.

### Which readability formula is best?

Depends on use case. Flesch-Kincaid: most widely cited, default for SEO tools (Yoast). Use for general content. Gunning Fog: best for business and journalism. Use for B2B and editorial content. SMOG: best for healthcare and government. Use for patient-facing or regulatory content. Coleman-Liau: best when syllable counting is unreliable (technical terms, proper nouns). Automated Readability Index (ARI): best when speed and consistency matter more than fine accuracy. Our recommendation: look at all 5 (especially the AVERAGE) — single-formula scores can mislead.

### Is the readability score the same in the US, UK, Canada, and Australia?

Yes — readability formulas don't have geographic variants. They measure properties of English text (sentence length, word syllables) that are the same regardless of which English-speaking country you're in. What DIFFERS is the GRADE LEVEL INTERPRETATION, since school systems vary. US grade 8 ≈ UK Year 9 ≈ Canadian grade 8 ≈ Australian year 9. So a Flesch-Kincaid Grade 8 score means roughly the same reading difficulty in all four countries, but the local 'grade' label may differ by 1 year.

### Can I use this readability calculator for non-English text?

Technically yes — the formulas will run on any text. But the SCORES WILL NOT BE MEANINGFUL for non-English languages. The formulas were calibrated against English-language reading research from the 1940s-1970s. Languages with different syllable structures (Japanese, Chinese), word lengths (German compound words), or sentence structures (Spanish, Italian) need language-specific readability formulas. For Spanish, use Fernández Huerta or Szigriszt-Pazos. For German, use Wiener Sachtextformel. For Russian, use Oborneva. Our calculator doesn't currently support these — it's English-only.

### How long should sentences be for good readability?

Aim for an AVERAGE sentence length of 15-20 words for general content, and a MAX of 25-30 words for any single sentence. Variety helps — alternate short (5-10 word) sentences with longer (20-25 word) ones for rhythm. Sentences over 40 words almost always hurt readability dramatically. Famous test: read your sentence aloud in one breath. If you can't, it's too long. Hemingway's writing averages 14 words/sentence; modern technical writing often hits 25-30 (too high); academic writing routinely hits 30-40 (only appropriate in academic context).

### Why does readability matter for content marketing?

Three reasons. (1) ENGAGEMENT — easier content has lower bounce rates, higher dwell time, more shares. Backlinko data shows top-ranking content averages grade 7-8 reading level. (2) ACCESSIBILITY — about 14% of US adults read below 8th-grade level. Content above 10th-grade excludes them entirely. The WCAG accessibility guideline recommends 9th-grade or below for general audiences. (3) CONVERSION — A/B tests consistently show simpler copy converts 20-50% better. The harder it is to understand your value prop, the more readers drop off before the CTA. Our content readability checker helps you hit the conversion-friendly sweet spot.

## Deep Dive

Whether you're a content marketer optimizing blog copy for SEO, a copywriter making landing pages accessible, an educator assessing student writing, or a healthcare communicator hitting plain-language requirements — this readability score calculator runs all 5 industry-standard formulas on any text you paste. Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog Index, SMOG Index, Coleman-Liau Index, and Automated Readability Index (ARI) — plus the average across all 5 as a single composite metric. Real-time updates as you type. No signup, no character limit. Below: how each formula works, when to use each, what grade level your content should target, and how to actually improve a score.

### How Readability Score Calculators Work: The Two Underlying Signals

Every readability formula in widespread use combines just two underlying signals: **SENTENCE LENGTH** (longer sentences are harder to follow) and **WORD COMPLEXITY** (longer or multi-syllable words are harder to process). The formulas differ in how they measure these signals (syllable count vs character count) and how they weight them in the final output.

- **Flesch Reading Ease** uses syllables per word + words per sentence, scaled 0-100.
- **Flesch-Kincaid** uses the same inputs but outputs a US grade level.
- **Gunning Fog and SMOG** use COMPLEX WORDS (3+ syllables) as a proxy for word difficulty.
- **Coleman-Liau and ARI** use CHARACTER COUNT instead of syllables — easier to automate.

Our readability score calculator runs all 5 in real-time as you type, plus shows the underlying counts (words, sentences, syllables, complex words, average sentence length) so you can see what's driving the score.

### Flesch Reading Ease: The 0-100 Score Most People Recognize

**Flesch Reading Ease** (formula by Rudolf Flesch, 1948) is the most widely cited readability metric. Formula: 206.835 − 1.015 × (words/sentences) − 84.6 × (syllables/words). Output is a 0-100 score where **HIGHER MEANS EASIER**.

Standard interpretation:

- 90-100 very easy (5th grade)
- 80-89 easy (6th grade)
- 70-79 fairly easy (7th grade)
- 60-69 plain English (8th-9th grade)
- 50-59 fairly difficult (10th-12th)
- 30-49 difficult (college)
- 0-29 very confusing (postgraduate)

For general digital content targeting US adults, aim for 60-75. Marketing copy and consumer apps push 70-85. Academic writing typically scores 30-50.

Yoast SEO highlights Flesch Reading Ease as the default readability metric in its WordPress plugin — so SEO-optimized content tends to target Flesch 60+.

### Flesch-Kincaid Grade Level: US School Grade Output

**Flesch-Kincaid Grade Level** (Kincaid et al., 1975, US Navy) converts readability to a US school grade. Formula: 0.39 × (words/sentences) + 11.8 × (syllables/words) − 15.59.

- Output 8.0 means an 8th-grader can read it.
- 12.0 = high school senior.
- 16.0 = college senior.
- 20.0 = postgraduate.

US Department of Defense, IRS, many state DMVs, and most US government agencies use Flesch-Kincaid to ensure public documents are accessible — targets are typically grade 8 or below. The 'Plain Writing Act of 2010' codified this for federal agencies.

Our Flesch-Kincaid calculator outputs grade level alongside the other 4 formulas; the AVERAGE across all 5 is usually the most reliable single number for editorial decision-making.

### Gunning Fog Index: Business Writing's Favorite Metric

**Gunning Fog Index** (Robert Gunning, 1952) was developed specifically for business writing and remains the favorite of editorial professionals. Formula: 0.4 × [ (words/sentences) + 100 × (complex words / total words) ]. **'Complex words'** = words with 3+ syllables, EXCLUDING common -ing/-ed/-es suffixes and proper nouns. Output is the **YEARS OF FORMAL EDUCATION** needed to understand the text on first reading.

- Most US business publications target 11-13 (high school junior to first-year college).
- Time magazine averages 11.
- The Wall Street Journal averages 12-13.
- Academic journals score 16-20.

Our Gunning Fog index calculator uses the standard implementation with suffix exclusion built into the syllable counter.

### SMOG Index: The Healthcare and Government Standard

**SMOG (Simple Measure of Gobbledygook) Index** by G. Harry McLaughlin (1969) is the formula of choice for healthcare and government documents because it predicts the grade level needed for **100% COMPREHENSION** (vs Flesch-Kincaid which predicts ~75% comprehension). Formula: 1.0430 × √(complex words × 30/sentences) + 3.1291. Where 'complex words' = words with 3+ syllables.

The CDC, NIH, US Department of Health and Human Services, and most US state health departments target SMOG ≤ 8 for patient-facing content. The UK NHS targets SMOG ≤ 9 for patient information leaflets.

Our SMOG index calculator uses McLaughlin's original 1969 formula — the result is typically 1-2 points higher than Flesch-Kincaid for the same text (SMOG is intentionally conservative).

### Coleman-Liau Index and ARI: Character-Based Formulas

**Coleman-Liau Index** (Meri Coleman and T.L. Liau, 1975) and **Automated Readability Index** (Senter and Smith, 1967, US Air Force) both sidestep the unreliability of syllable counting by using **CHARACTER COUNT** instead.

- Coleman-Liau formula: 0.0588 × L − 0.296 × S − 15.8, where L = average letters per 100 words, S = average sentences per 100 words.
- ARI formula: 4.71 × (characters / words) + 0.5 × (words / sentences) − 21.43.

Both output US grade levels. Coleman-Liau and ARI are the preferred formulas when you're scoring text with lots of technical terms, proper nouns, or made-up jargon — because syllable counting on those words is heuristic and error-prone, while character counting is exact. Most automated tools default to Coleman-Liau when syllable parsing is expensive.

### What Reading Level Should Your Blog Content Target?

Different content types have different reading-level sweet spots.

- **SOCIAL MEDIA & EMAIL:** grade 5-6 (Flesch Reading Ease 75-85). Maximum reach, immediate scan-and-go.
- **CONSUMER BLOGS & MARKETING:** grade 7-8 (Flesch 65-75). This is the SEO sweet spot per Backlinko, Yoast, and SurferSEO research. Top-ranking content consistently lands here.
- **B2B BLOGS & WHITE PAPERS:** grade 9-10 (Flesch 50-65). Professional audience tolerates slightly denser writing.
- **TECHNICAL DOCUMENTATION:** grade 10-12 (Flesch 40-55). Industry experts expect terminology.
- **ACADEMIC PAPERS:** grade 14-18 (Flesch 20-40). Don't optimize academic prose down to 8th grade — it's read by specialists.
- **LEGAL & MEDICAL CONSENT DOCUMENTS:** grade 6-8 mandated by many jurisdictions.

Our readability assessment tool helps you pin down which target you're hitting.

### How to Improve Your Readability Score: 6 Proven Techniques

Ranked by impact on score.

- **(1) SHORTEN SENTENCES.** Single biggest lever. Every sentence over 30 words should be split. Average sentence length under 20 words moves Flesch up 10+ points.
- **(2) REPLACE 3+ SYLLABLE WORDS** with simpler synonyms when meaning is preserved. 'Utilize' → 'use'. 'Demonstrate' → 'show'. 'Facilitate' → 'help'. 'Implement' → 'do'. Cuts Gunning Fog and SMOG substantially.
- **(3) USE ACTIVE VOICE.** 'The team shipped the feature' beats 'the feature was shipped by the team'. Active voice typically uses fewer words.
- **(4) BREAK UP PARAGRAPHS.** Walls of text feel harder regardless of actual readability score — and they hurt engagement metrics that DO affect SEO.
- **(5) REMOVE FILLER PHRASES.** 'In order to' → 'to'. 'Due to the fact that' → 'because'. 'At this point in time' → 'now'.
- **(6) READ ALOUD** before publishing. If you stumble, the text is too dense — even if the score looks fine.

### Readability and SEO: Why Easier Content Ranks Better

Google's algorithms don't directly score readability — but they DO measure engagement signals that strongly correlate with readability. Backlinko's analysis of 11.8 million search results found that top-ranking pages average grade 7-8 reading level. SurferSEO data confirms the same pattern across industries. Yoast SEO's WordPress plugin explicitly flags content above 9th-grade level as a 'readability problem'.

Why does this matter? Three engagement mechanisms.

- **(1) DWELL TIME:** easier content is read more fully before users bounce back to search results.
- **(2) SOCIAL SHARES:** shared content correlates with simpler prose.
- **(3) BACKLINKS:** writers cite content they can quickly skim and quote.

All three feed back into ranking. The SEO readability checker on this page outputs the same Flesch-Kincaid grade Yoast uses, so you can pre-validate before publishing.

### Using the Readability Calculator for Student Writing Assessment

Educators use readability score calculators in three common workflows.

- **(1) ASSESSING STUDENT WORK:** paste a student's essay to gauge whether vocabulary and sentence complexity is appropriate for grade level. Concerning if grade 5 student writes at grade 10 (likely AI-assisted) or grade 10 student writes at grade 5 (skill gap).
- **(2) PICKING TEXTS FOR READING ASSIGNMENTS:** paste a candidate passage to confirm it sits at the right grade level for the class. Below-level texts won't challenge; above-level texts will frustrate.
- **(3) TEACHING WRITING IMPROVEMENT:** show students their first draft's grade level, then re-test after rounds of revision to demonstrate concrete improvement.

Our readability checker for students is free, no signup, no character limit — useful for K-12 classrooms and university composition courses alike.

### Readability for Plain Language Compliance (Government, Healthcare, Legal)

Multiple jurisdictions mandate plain language for public-facing documents.

- **US PLAIN WRITING ACT (2010):** federal agencies must write in plain language; informally targets grade 8 or below.
- **UK GOV.UK CONTENT GUIDELINES:** target Year 9 reading age (≈ US grade 8).
- Healthcare informed consent forms in many US states are mandated at grade 6-8.
- **EU REGULATIONS** often require 'clear and intelligible' language, interpreted in practice as ≤ grade 9.
- **WCAG 2.1** web accessibility guidelines (W3C) recommend grade 9 or below for general audiences (Level AAA).

Our text readability analyzer outputs all formulas including SMOG (preferred for healthcare) and Flesch-Kincaid (preferred for government). For compliance-critical content, run multiple formulas and target the AVERAGE at the required grade level — single-formula scores can be optimistic.

### Common Readability Score Mistakes and How to Avoid Them

Avoidable mistakes that lead to misleading readability assessments.

- **(1) RELYING ON ONE FORMULA.** Each formula has biases (Gunning Fog is sensitive to long words, SMOG to complex words, Coleman-Liau to character density). Use the AVERAGE across multiple formulas.
- **(2) IGNORING SAMPLE SIZE.** Readability formulas are calibrated for 100+ word samples. Scoring a 20-word marketing headline gives nonsense results. Paste at least a paragraph.
- **(3) CONFLATING READABILITY WITH QUALITY.** Easy-to-read prose can be vapid; complex prose can be excellent. Readability is one signal, not the goal.
- **(4) OPTIMIZING FOR THE FORMULA, NOT THE READER.** Short choppy sentences hit good scores but feel robotic. Use readability as a guide, not a straitjacket.
- **(5) IGNORING AUDIENCE CONTEXT.** A grade-12 reading level is wrong for consumer marketing but right for legal contracts. Match the score to the audience, not to a universal 'best' target.
- **(6) MISSING THE FORMATTING IMPACT.** Readability formulas don't see your paragraph breaks, bullet points, or headings — but readers do. A wall-of-text grade-7 essay still feels harder than a bullet-pointed grade-9 one.

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## Authoritative Sources

- [National Institutes of Health (US) — Plain Language Guidelines](https://www.nih.gov/institutes-nih/nih-office-director/office-communications-public-liaison/clear-communication/plain-language) — Official US federal guidance on plain language and readability targets for health content
- [Plain Language Action and Information Network (PLAIN)](https://www.plainlanguage.gov/guidelines/words/) — US Plain Writing Act guidance — recommends 8th-grade reading level or below for federal documents
- [UK Government Service Manual — Writing for GOV.UK](https://www.gov.uk/guidance/content-design/writing-for-gov-uk) — Official UK Government Digital Service guidance — targets 9-year-old reading level (UK Year 5)
- [WCAG 2.1 — W3C Accessibility Guidelines (Readable)](https://www.w3.org/TR/WCAG21/#readable) — Web Content Accessibility Guidelines on text readability for international web standards
- [DuBay (2004) — The Principles of Readability](https://www.impact-information.com/impactinfo/readability02.pdf) — Authoritative academic survey of readability formulas, their history, and validity research
- [Mailchimp — Content & Voice Style Guide on Readability](https://styleguide.mailchimp.com/grammar-and-mechanics/) — Industry-standard content guide referenced by content marketers worldwide

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