Readability Checker – Flesch Reading Ease & Grade
Measure the approximate reading difficulty of English prose using established formulas. Review sentence length and syllable estimates before you revise.
Enter English text to estimate readability.
English-only heuristic. Syllable counts and sentence boundaries are approximate. Scores are not a proof of comprehension, a grammar grade or a ranking signal.
What does Flesch Reading Ease measure?
The Flesch Reading Ease formula uses average sentence length and syllables per word to estimate how easy English prose is to read. A higher score usually means simpler text under this metric, but technical writing, names, abbreviations and diverse audiences can make the estimate misleading.
The formula is 206.835 − 1.015 × (words / sentences) − 84.6 × (syllables / words). The result can occasionally go outside the familiar 0–100 range for unusual input. We calculate syllables with a small deterministic rule-based estimator, not a pronunciation dictionary.
What is the Flesch-Kincaid grade level?
The related Flesch-Kincaid formula estimates the equivalent United States school grade level for English-language reading difficulty. It is 0.39 × (words / sentences) + 11.8 × (syllables / words) − 15.59. The output is an estimate, not a classification of any individual reader's skills.
How to make English text more readable
- Paste at least a paragraph of complete English sentences for a less unstable sample.
- Identify sentences that combine too many ideas. Shorten them only when it improves meaning.
- Replace unnecessary jargon with familiar terms while keeping precise definitions.
- Read the draft aloud and ask a real reader whether the explanation is clear.
The formulas are documented in Microsoft's readability statistics guide. The underlying word, sentence and syllable counting rules can differ between applications, so do not expect identical numeric scores.
Limitations of automatic readability scores
This calculator is intended for English. It ignores words written entirely in other scripts, and abbreviations such as Dr. can confuse sentence detection. For text shorter than 30 English words, the tool marks scores as unstable. A reading-ease number cannot measure accuracy, inclusiveness, meaning or a person's comprehension.
Frequently asked questions
Is a high readability score always better?
No. A concise technical explanation may appropriately use specialist terminology. Match the language to the intended readers and preserve important meaning.
Does Google rank pages by Flesch score?
Do not treat this score as a direct Google ranking target. It is an editing heuristic, not a search ranking forecast.
Does PostChars send the analyzed text anywhere?
No. The readability analysis runs in the browser and does not submit your text to a PostChars server.