Free Online Readability Checker

A readability score estimates how easy or difficult a piece of text is to read. Scores are typically expressed as a US grade level (e.g., Grade 8 means an average 8th grader can understand it) or on a scale like Flesch Reading Ease (0-100, higher is easier).

Flesch Reading Ease rates text on a 0-100 scale. Scores 60-70 are considered standard (understandable by 13-15 year olds). Scores above 80 are easy to read, while scores below 30 are very difficult. It is based on average sentence length and syllables per word.

The Flesch-Kincaid Grade Level converts readability into a US school grade. A score of 8.0 means the text is appropriate for an 8th grader. Most popular writing targets grade 7-8. The formula uses average sentence length and average syllables per word.

The Gunning Fog Index estimates the years of formal education needed to understand text on first reading. It focuses on sentence length and the percentage of complex words (3+ syllables). A score of 12 means the text requires a high school senior's reading level.

The Coleman-Liau Index uses the average number of letters and sentences per 100 words to estimate grade level. Unlike other formulas, it counts characters instead of syllables, making it more reliable for computer analysis since it avoids syllable-counting heuristics.

For general audiences, aim for grade 7-8 (Flesch Reading Ease 60-70). For technical writing, grade 10-12 is acceptable. For web content and marketing, grade 6-8 maximizes engagement. Newspapers typically write at grade 8-10.

Use shorter sentences (under 20 words average). Choose simpler words over complex ones. Use active voice. Break long paragraphs into shorter ones. Avoid jargon unless writing for a specialized audience. Read your text aloud — if you stumble, simplify.

Readability formulas are statistical estimates based on surface features like word and sentence length. They do not measure comprehension, context, or domain knowledge. Use them as guidelines, not absolute measures. Comparing multiple scores gives a more reliable picture than any single formula.

It depends on your audience. Scores above 70 are appropriate for general consumer content, marketing copy, and journalism aimed at a broad readership. Scores of 50–70 suit business reports and professional articles. Scores below 30 indicate dense academic or legal text. Most web content performs best — and ranks better in search — when it scores above 60.

Each formula was developed independently using different corpora and weighs different factors. Flesch-Kincaid focuses on syllable count per word and words per sentence. Gunning Fog counts complex words (three or more syllables). Coleman-Liau uses character count rather than syllable count. Because they measure slightly different things, the scores won't always agree — looking at the range across all four gives a more reliable picture than relying on any single score.

Indirectly, yes. Google doesn't use readability formulas as a direct ranking signal, but readable content correlates with lower bounce rates, longer time on page, and more backlinks — all of which do influence rankings. Readable content is also more likely to be selected as a featured snippet, since Google favors concise, direct answers to question queries. Simpler writing also tends to match more natural language search queries.