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SEO Readability

Calculate standard readability scores, evaluate sentence complexities, and optimize content structure for web readers.

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Protected Keywords (AI will not simplify these)Optional

Readability Algorithm

Very Difficult•College Graduate

Academic, scientific, or highly professional prose requiring post-graduate reading levels.

This content is hard to read. Use AI to simplify sentences and replace complex vocabulary.

Simplify with AI (Costs 2 Credits)

About the Algorithm

Flesch Reading Ease

Measures readability based on sentence length and syllable density. Higher scores mean easier reading.

Formula206.835 - 1.015 × (Words/Sentences) - 84.6 × (Syllables/Words)

Linguistic Metrics

Words0

Sentences0

Syllables0

Reading Time0 min

1 Simple Sentences

Keep average sentence lengths under 15 words. Shorter layouts reduce cognitive friction, boosting time-on-page metrics.

2 Plain English standard

Aim for Flesch scores between 60 and 70 (8th/9th grade equivalent). This ensures your text is easily readable by the general public.

3 Reading retention

Highly readable content leads to improved search ranking factors by reducing bounce rates and encouraging user click-through interactions.

Readability Formulas & Search Engine Optimization

Readability represents a critical component of search engine optimization. Search engine crawlers evaluate user engagement indicators such as dwell time, click-through rates, and bounce rates. When a visitor lands on page content that is easy to comprehend, they stay longer and browse further, signaling high-quality content to search algorithms.

Our analyzer helps you evaluate your text using four industry-standard formulas, ensuring your writing is perfectly tailored to your target audience.

Readability Best Practices

1
Target Plain Language
Focus writing styles to achieve Flesch Reading Ease scores over 60, catering to mainstream web demographics.
2
Trim Sentence Lengths
Sentences spanning over 25 words confuse readers. Break long paragraphs into shorter separate thoughts.
3
Limit Multi-Syllabic Terms
Minimize complex jargon. Use simple words (e.g. 'use' instead of 'utilize') to reach a wider target audience.
4
Organize with Subheadings
Break sections into digestible parts under H2/H3 headers. Scan-friendliness improves reading flow.

Supported Readability Algorithms

Flesch Reading Ease

Best for: general web copywriting, blog articles, and public-facing content.

The global benchmark for general readability. It rates text on a 100-point scale. The higher the score, the easier it is to read. Web standards recommend target scores between 60 and 70 (8th-9th grade level).

Formula206.835 - 1.015 × ASL - 84.6 × ASW

Gunning Fog Index

Best for: corporate communications, research documents, and whitepapers.

Estimates the number of formal education years required to understand the text. A score of 12 represents high school senior level, while scores above 16 indicate graduate school complexity. Lower scores ensure accessibility.

Formula0.4 × [ ASL + 100 × (Complex Words / Words) ]

Dale-Chall Readability

Best for: children's literature, textbooks, and non-native English instruction.

Uses a pre-compiled dictionary of 3,000 familiar English words. Content containing words outside this list gets penalized, making this formula extremely reliable for assessing vocabulary complexity rather than just syllables.

Formula0.1579 × (% Difficult Words) + 0.0496 × ASL

Automated Readability Index (ARI)

Best for: technical specs, manuals, and software guides.

Calculates character count per word rather than syllable count, which provides a highly sensitive grade-level output. Very common in technical documentation writing tools.

Formula4.71 × (Characters / Words) + 0.5 × ASL - 21.43

SMOG Grade (Simple Measure of Gobbledygook)

Best for: medical, healthcare, consumer safety, and legal readability checks.

Measures readability by counting polysyllabic words. Widely considered the gold standard for healthcare documentation due to its focus on word complexity and accuracy.

Formula1.0430 × √[ 30 × (Polysyllable Count / Sentences) ] + 3.1291