What is a good readability score for a website?

For most websites, a Flesch Reading Ease score of 60-70 is ideal — roughly equivalent to a US 8th-9th grade reading level, readable by the majority of adult internet users. Marketing and e-commerce content should target 65-75 for maximum accessibility. News articles typically score 60-65. Technical documentation can be lower (40-55) if the audience is specialists. Academic and legal documents often score 20-40. Google itself uses readability as one of many signals in ranking content quality.

What is the Flesch Reading Ease formula and how is it calculated?

The Flesch Reading Ease score is calculated as: 206.835 − (1.015 × average sentence length) − (84.6 × average syllables per word). The result is a score from 0 to 100. Higher scores mean easier text. Scores above 90 are very easy (5th grade). 70-80 is easy (6th grade). 60-70 is standard. 50-60 is fairly difficult. 30-50 is difficult (college level). Below 30 is very difficult (academic/professional). The formula was developed by Rudolf Flesch in 1948 and remains the most widely used readability metric.

What is the difference between Flesch-Kincaid, Gunning Fog, SMOG and ARI?

Each formula measures readability slightly differently. Flesch-Kincaid Grade Level converts Flesch into a US school grade equivalent. Gunning Fog counts 'complex words' (3+ syllables) and is commonly used in journalism. SMOG (Simple Measure of Gobbledygook) is the most accurate formula for health communications — it requires at least 30 sentences for accuracy. Coleman-Liau uses character counts rather than syllables, making it less ambiguous. ARI (Automated Readability Index) also uses characters and is the most objective since it doesn't require syllable estimation. Running all formulas simultaneously gives you a more reliable overall picture than any single score alone.

What is vocabulary richness and what does the Type-Token Ratio measure?

Vocabulary richness, measured by Type-Token Ratio (TTR), is the percentage of unique words in your text: TTR = (unique words / total words) × 100. A TTR of 100% means every word is used exactly once — extremely varied vocabulary. As text gets longer, TTR naturally drops because common words inevitably repeat. For blog posts and articles (500-1000 words), a TTR of 50-70% suggests good vocabulary diversity. Below 40% may indicate repetitive or formulaic writing. Very high TTR in short texts is normal and expected.

How do I improve my readability score quickly?

The two most impactful changes are: 1) Shorten your sentences. Every formula penalises long sentences. Split any sentence over 25 words into two. This alone can move a score by 5-15 points. 2) Replace complex words with simpler alternatives. 'Utilise' → 'use'. 'Demonstrate' → 'show'. 'Approximately' → 'about'. 'Subsequently' → 'then'. Use the complex words list our tool provides to find specific candidates. Beyond these two, adding subheadings (which break up long paragraphs), using active voice, and preferring concrete nouns over abstract ones all contribute to better readability scores and, more importantly, better reader comprehension.

Writing Tools

Free Readability Checker — 7 Formulas, Sentence Map & Famous Benchmarks

Name: Readability Checker
Author: PursTech

The most complete free readability tool available. Calculate seven industry-standard readability scores simultaneously, set a target audience and see exactly how close your text is, and compare your writing to famous documents.

Every metric updates live as you type — no button, no wait.

Target Audience

The rapid advancement of artificial intelligence technology has created unprecedented opportunities for businesses across virtually every industry sector. However, implementing these sophisticated systems effectively requires careful consideration of numerous complex factors. Organisations must evaluate their existing infrastructure capabilities, workforce competencies, and strategic objectives before committing to substantial technological transformation initiatives.

The successful integration of artificial intelligence into established operational workflows necessitates comprehensive planning, significant resource allocation, and ongoing maintenance commitments from dedicated technical personnel. Without adequate preparation and organisational change management, even the most advanced technological implementations frequently encounter substantial resistance from existing staff members.

Clear communication helps teams succeed. Short sentences are easier to read. People understand simple words faster.

1018 chars

111

Words

Sentences

13.9w

Avg length

1 min

Read time

Flesch Reading Ease

Very Difficult

Audience Match

👤 General Adult

✗ Off target

All 7 Formulas

Flesch Reading Ease0

Difficult — requires educated readers

Flesch-Kincaid GradeGrade 21.7

US school grade 22 reading level

Gunning Fog27.2

Above newspaper level

SMOG Index18.8

Best validated for health communications

Coleman-Liau29.3

Character-based formula — no syllable ambiguity

ARI23.4

Automated — uses characters per word

Dale-Chall16.4

Based on 3,000 familiar words — contains unfamiliar words

Where Your Text Sits

You

Insurance

Academic

Harvard

New

Harry

Twitter

0 — Very Hard100 — Very Easy

Sentence Difficulty Map

≤15w16-25w26-35w>35w

18w

13w

19w

24w

21w

🟡 Sentences >20w: 2🔴 Sentences >30w: 0

Vocabulary Richness

88%

Type-Token Ratio

98 unique words out of 111 total

Complex Words

60 (3+ syllables)

organisational (6)opportunities (5)effectively (5)consideration (5)organisations (5)capabilities (5)technological (5)initiatives (5)operational (5)necessitates (5)implementations (5)communication (5)advancement (4)artificial (4)intelligence (4)technology (4)unprecedented (4)businesses (4)implementing (4)sophisticated (4)

💡 Personalised Improvement Tips

›54% complex words (target <15%). Try replacing some from the list above.

›Avg word has 2.7 syllables. Favour shorter words — they improve every formula simultaneously.

📐7 Readability Formulas

Flesch, Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, ARI and Dale-Chall — all calculated simultaneously with progress bars.

🎯Target Audience Mode

Set your target reader (5th grade → academic) and see a match score showing exactly how close your text is to that level.

📚Famous Text Benchmarks

See where your text sits relative to Harry Potter, NYT articles, Harvard Law Review and insurance policies on a single visual scale.

📊Sentence Difficulty Map

A colour-coded bar chart with one bar per sentence — instantly reveals where in your text the density is highest.

🔍Annotated Text View

Toggleable highlights: long sentences in yellow/red, complex words underlined. Shows the problem areas directly in your text.

📈Vocabulary Richness (TTR)

Type-Token Ratio measures how varied your vocabulary is — a key indicator of writing quality that no other free tool shows.

Who uses this tool?

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Content Writers & SEOs: Verify blog posts and landing pages target the right reading level for your audience before publishing.

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Educators & Academics: Check whether reading materials are appropriate for student grade levels, and measure academic paper complexity.

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UX & Product Writers: Ensure product copy, onboarding text and help articles are simple enough for all users — including non-native speakers.

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Health & Legal Communicators: SMOG formula is the standard for health literacy. Ensure patient-facing documents meet plain-language requirements.

PursTech vs Hemingway vs WebFX vs Readable.io

Readability tool feature comparison

Feature	PursTech	Hemingway	WebFX	Readable
Number of formulas	7	1	7	6
Target audience mode	✓	—	—	✓
Famous text benchmarks	✓	—	—	—
Sentence difficulty map	✓	—	—	—
Annotated text highlights	✓	✓	—	—
Complex word list	✓	—	—	✓
Vocabulary richness (TTR)	✓	—	—	—
Sentence length distribution	✓	—	—	—
Download analysis report	✓	—	—	paid
Live update as you type	✓	✓	—	—
100% free, no account	✓	—	✓	—

How to Use the Readability Checker

Set your target audience

Choose who you're writing for — 5th grade, high school, general adult, college or academic. The tool shows your audience match percentage.

Paste your text

All 7 readability formulas update live as you type. The sample text is pre-loaded so you can see the tool working immediately.

Review scores and sentence map

Check all 7 formula scores, find your position on the famous text benchmark scale, and read the sentence difficulty map to spot dense paragraphs.

Annotate and improve

Switch to Annotate view to highlight long sentences and complex words directly in your text. Use the improvement tips to raise your score.

❓ Frequently Asked Questions

What is a good Flesch Reading Ease score and what should I target?+

The Flesch Reading Ease score runs from 0 (unreadably complex) to 100 (extremely simple). Here's how to interpret it and what to target by content type: 90-100: Very Easy — 5th grade level. Consumer product instructions, children's content. 80-90: Easy — 6th grade. Conversational copy, social media, simple emails. 70-80: Fairly Easy — 7th grade. Most marketing copy, landing pages. 60-70: Standard — 8th-9th grade. Blog posts, news articles, general web content. This is the sweet spot for most audiences. 50-60: Fairly Difficult — 10th-12th grade. Professional B2B content, technical blogs. 30-50: Difficult — College level. Academic blogs, whitepapers, research summaries. 0-30: Very Difficult — Graduate level. Academic papers, legal documents, medical literature. Google doesn't use Flesch scores directly in its algorithm, but clear, readable content performs better because users stay longer, bounce less, and share more — all of which are indirect ranking signals.

What's the difference between all 7 readability formulas?+

Each formula was designed for a slightly different purpose and uses different inputs: Flesch Reading Ease (1948): The oldest and most cited. Uses sentence length + syllables per word. Gives a 0-100 score where higher = easier. Best for: general writing quality assessment. Flesch-Kincaid Grade Level (1975): Converts Flesch into a US school grade level. Developed for the US Navy to assess technical manuals. Best for: quick grade-level equivalence. Gunning Fog Index (1952): Counts 3-syllable words as "complex." Grade-level output. Best for: journalism and business writing. Robert Gunning created it specifically for newspapers. SMOG Index (1969): Simple Measure of Gobbledygook. Counts polysyllabic words in 30 sentences. The most validated formula for health communications — recommended by the CDC and NHS. Best for: health, safety and legal plain-language compliance. Coleman-Liau Index (1975): Uses character counts rather than syllables, so it's less subjective. Best for: computerised text analysis where syllable counting is unreliable. ARI (Automated Readability Index, 1967): Uses characters per word and words per sentence. Developed for real-time monitoring on typewriters. Best for: objective analysis without syllable ambiguity. Dale-Chall (1948, updated 1995): Compares words against a list of 3,000 familiar words. Grades difficult unfamiliar words more harshly. Best for: educational and children's content assessment.

What are the famous text benchmarks and how should I use them?+

The benchmarks show where well-known published texts score, giving you real-world context for your own score. Here are the reference points used: Harry Potter (J.K. Rowling): Flesch ~72 — This is the target for young adult and accessible general fiction. Rowling's prose is famously readable. New York Times: Flesch ~65 — The standard for quality journalism. Clear to educated adults but not dumbed down. Harvard Business Review: Flesch ~43 — Academic business writing. Appropriate for professional audiences. Academic Research Papers: Flesch ~30 — Dense, specialised language assumed for expert readers. Insurance Policies: Flesch ~16 — Notoriously difficult. Often cited as a readability failure case study. Use the benchmark scale to quickly understand your text's difficulty in concrete terms. "I'm similar to an NYT article" is more intuitive than "I scored 63 on Flesch."

What is vocabulary richness and why does it matter?+

Vocabulary richness is measured by the Type-Token Ratio (TTR): the percentage of unique words out of total words. A TTR of 60% means 60 in every 100 words are distinct. Why it matters: High TTR suggests varied, precise vocabulary — a mark of skilled writing. Low TTR indicates repetitive, formulaic language that can feel monotonous to read. Important caveat: TTR naturally decreases in longer texts because common words (the, and, is, you) inevitably repeat. For short texts (under 200 words), TTR above 70% is excellent. For medium texts (500-1000 words), 50-65% is strong. For long texts (2000+ words), 40-55% is expected and acceptable. When improving vocabulary richness: identify the most repeated non-stop words from our overused words analysis, and replace some instances with synonyms where meaning is preserved. But don't sacrifice clarity for variety — precision is more important than diversity in technical writing.

What does the sentence difficulty map show and how do I use it?+

The sentence difficulty map displays one horizontal bar per sentence in your text. Each bar's length represents the number of words in that sentence. The colour indicates difficulty: 🟢 Green (≤15 words): Short, easy sentences. Readers process these instantly. 🟡 Yellow (16-25 words): Moderate length. Acceptable but watch the density. 🟠 Orange (26-35 words): Long sentences. Each one is a reading challenge. 🔴 Red (>35 words): Very long. These almost always need to be split. How to use it: Look for clusters of orange and red bars — those are the sections of your text with the highest cognitive load. Click the "Annotate Text" button to see those sentences highlighted directly in the text, then split the longest ones first. Splitting one 40-word sentence into two 20-word sentences can meaningfully improve your Flesch score. Best practice: no more than 15-20% of your sentences should be over 25 words for general-audience writing.

Why Readability Matters — for SEO, Education and Communication

Readability is one of the most consistently underestimated factors in effective communication. Studies from the Nielsen Norman Group repeatedly find that web users read at most 20-28% of words on a page in detail — they scan. Complex sentences and unfamiliar vocabulary break that scanning pattern, causing users to give up and leave. For commercial content, this means higher bounce rates, lower time-on-page, and fewer conversions — all compounding negative signals to search engines.

In education, reading level accuracy is critical. Assigning materials significantly above a student's level produces frustration and disengagement. Below their level and they aren't challenged to grow. The seven formulas this tool provides were each developed for specific domains: Flesch for general use, SMOG for health and safety communications (where plain language compliance is often legally mandated), and Dale-Chall for children's educational materials. Using the right formula for your domain gives more meaningful results than any single metric.

Plain language advocates in government and healthcare have demonstrated measurable outcomes from improving readability. The US Center for Plain Language found that rewriting a Medicare form from grade 14 to grade 8 increased correct completion from 37% to 92%. The NHS's Plain English Campaign has shown similar results with patient information leaflets. These real-world outcomes are why organisations from the FDA to the UK Government Digital Service have adopted readability standards — and why measuring your content's grade level is genuinely important, not just an academic exercise.