Readability Checker

Free Readability Checker — Flesch-Kincaid, Gunning Fog & More

Readable content keeps visitors on your page longer, reduces bounce rates, and earns more shares and backlinks. Hard-to-read content drives people away regardless of how valuable the information is. This free Readability Checker analyzes your text using multiple established readability formulas — Flesch-Kincaid Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog Index, SMOG Index, and Coleman-Liau Index — giving you a comprehensive view of how accessible your content is.

Paste any text to get instant readability scores across all formulas, plus specific recommendations for improving clarity. The tool identifies overly long sentences, complex words, and passive voice — the three main readability killers.

Readability optimization is a key part of on-page SEO. Google's NLP systems process text the same way human readers do — clear, direct sentences are easier to understand and extract meaning from, leading to better featured snippet eligibility and content quality assessments.

Readability Formulas Explained

Flesch Reading Ease (0–100). Higher scores are easier to read. 60–70 is plain English suitable for most audiences. Below 30 is academic/technical.

Flesch-Kincaid Grade Level. Maps to US school grade level. A score of 8 means an 8th grader can understand it. Target 6–8 for broad web audiences.

Gunning Fog Index. Estimates years of education needed to understand the text. A score above 12 suggests the text may be too complex for general audiences.

SMOG Index. Simple Measure of Gobbledygook. Counts polysyllabic words to estimate required education level. Good for health and government communications.

Coleman-Liau Index. Based on characters per word and sentences per 100 words. Unlike other formulas, it does not count syllables. Tends to be accurate for academic writing.

How to Improve Readability

Shorten sentences. Aim for an average sentence length of 15–20 words. Break complex sentences into two.

Use simpler words. Replace multi-syllable jargon with common equivalents. "Use" instead of "utilize". "Start" instead of "commence".

Use active voice. "The dog bit the man" (active) is clearer than "The man was bitten by the dog" (passive). Active voice shortens sentences and makes meaning clearer.

Related Tools

• Grammar Checker – Fix grammar, spelling, and style issues.
• Word Counter – Count words and estimate reading time.
• Keyword Density Checker – Analyze keyword usage in your content.

Frequently Asked Questions