Readability Score Checker

How readability scores work and what the numbers mean

Readability formulas estimate how easy or hard a piece of text is to read, expressed as a school grade level or a 0–100 score. They work by measuring things you can count — words per sentence, syllables per word, characters per word — and plugging them into a regression equation calibrated against reading-comprehension test data. They do not understand meaning; they measure structural complexity.

This tool calculates four standard readability metrics. The Flesch Reading Ease score runs from 0 (very hard) to 100 (very easy), where 60–70 is considered standard for a general audience. The Flesch-Kincaid Grade Level converts the same inputs into a US school grade (8.2 means an eighth-grader can understand it). The Gunning Fog Index estimates the years of formal education needed, so a Fog of 12 means roughly a high school senior. The Coleman-Liau Index uses character counts instead of syllable counts, making it faster to compute and arguably more consistent.

Syllable counting in English is a heuristic, not an exact science. This tool counts vowel groups (a, e, i, o, u, y), subtracts silent final e's, and enforces a minimum of one syllable per word. That gets about 90% of English words right. Words like "area" (3 syllables) and "fire" (1 syllable) are hard cases for any automated counter. The formulas tolerate this noise because they were calibrated against similarly imperfect counts.

All processing happens in your browser. Your text is never sent to a server, which matters if you are checking readability on client content, medical instructions, legal disclosures, or anything not yet published. The results update live as you type or paste.