Overview
Paste any text to estimate its Flesch-Kincaid Grade Level: 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59, a readability formula that maps sentence length and syllable complexity onto the approximate U.S. school grade a reader would need to comfortably follow the text. Longer sentences and longer, more syllable-heavy words push the score higher; short sentences built from short, common words push it lower. Syllables are counted with a plain vowel-group heuristic (each run of vowels counts as one syllable, with an adjustment for silent trailing "e" in words like "like" or "name") rather than a dictionary lookup, so the result is a genuine estimate, not an exact count - it's labeled that way in the output. Empty text, or text with no actual words, is handled with a clear message instead of a divide-by-zero error or a NaN result, and text with no sentence-ending punctuation is treated as one sentence rather than zero. Useful for checking whether a piece of writing matches its intended audience, from a children's book to technical documentation. Runs entirely client-side, so nothing you paste is uploaded anywhere.
Best for: Checking whether a piece of writing matches its intended audience's reading level
How to use this tool
- Paste or type your text. Anything from a single paragraph to a full article.
- Read the estimated grade level. Along with the word, sentence, and estimated syllable counts behind it.
- Simplify if needed. Shorter sentences and simpler, fewer-syllable words bring the grade level down.
Frequently asked questions
No - syllables are estimated using a vowel-group heuristic (each run of vowels counts as one syllable, with an adjustment for common silent-e endings) rather than a dictionary lookup, so it's a close approximation rather than a guaranteed-exact count. This is labeled clearly in the result.
The calculator shows a clear message asking for text to analyze, rather than attempting the calculation and producing a divide-by-zero error or a NaN result. Text with no sentence-ending punctuation is treated as a single sentence rather than zero, which would otherwise also cause a divide-by-zero.
It's the approximate U.S. school grade a reader would need to have completed to comfortably understand the text on a first read - for example, a score around 8 suggests writing understandable to an eighth grader. Most general-audience writing aims for somewhere in the 7-9 range; technical or academic writing often scores meaningfully higher.