Readability Score
Estimate the school grade level of any text — Flesch-Kincaid for English, an adaptive sentence-length formula for Chinese
Three formulas because one lies
Flesch Reading Ease, Flesch-Kincaid grade and Gunning Fog run together — agreement between them is the real signal.
Two formulas, one score
English text gets the standard Flesch-Kincaid Grade Level and Reading Ease score; Chinese text gets a sentence-length formula built for Chinese — you never get a score computed with the wrong language’s math.
Suggestions, not just numbers
Every metric maps to practical advice — split sentences that run too long, simplify wording that is too dense, or get told that your text already reads well.
Grade-level suggestions
The score updates live as you type or paste, with zero uploads: the analysis runs entirely in your browser, so your draft never leaves your device.
Frequently asked questions
What does the grade level mean?
The grade number approximates the US school year a reader needs to understand the text comfortably: 1-6 is roughly elementary school, 7-9 middle school, 10-12 high school, and 13+ college or graduate level. It is an estimate based on sentence and word statistics, not a formal test.
How is Chinese text scored?
The Flesch-Kincaid formula assumes spaces between words and counts syllables, so it does not transfer to Chinese. Chinese text is scored with an adaptive formula based on average sentence length in characters and the share of long sentences — the strongest structural predictors of Chinese reading difficulty.
How accurate is the score?
Accurate enough to compare texts and spot problems: long sentences and rare long words reliably lower the score. The syllable counter is a heuristic (abbreviations like "Mr." can split a sentence), and very short texts give an indicative score only.
Formula mechanics, briefly
| Score | Inputs | Reads as |
|---|---|---|
| Flesch ease | avg sentence length, avg syllables/word | 0–100, higher easier |
| F-K grade | same inputs weighted | US school grade level |
| Gunning Fog | complex words = 3+ syllables | years of education needed |
Syllable counting uses English heuristics (silent-e, -ed/-ing rules); other-language scores are indicative only. A hardest-sentences panel lists the five longest offenders so edits start where they matter.
Related tools
What is the Readability Score?
Readability scoring answers one question: roughly what school grade can comfortably read this passage. This tool grades pasted text live, pairs the number with a plain-language band from elementary to graduate level, and suggests concrete fixes when sentences run long.
Two formulas, honestly separated
English uses the standard Flesch-Kincaid grade — a weighted mix of average sentence length and average syllables per word — alongside the 0-to-100 Reading Ease scale. Chinese cannot use that formula, so it is graded by average sentence length instead: around 8 characters per sentence reads as early elementary, 25 to 35 as secondary school, 50-plus as university. The page always tells you which formula is scoring, and English-only extras like syllable counts hide themselves on Chinese text.
The supporting numbers
Four cards show sentence count, word or character count, average sentence length and the share of long sentences — over 25 words in English, over 40 characters in Chinese. Warnings name the exact problem: very long sentences, a high long-sentence share, or a sample too short to judge.
When you would use it
It settles debates in three places:
- Smooth a help-center article before release
- Check whether a translated page kept its reading level
- Settle an editing argument about a paragraph everyone finds heavy
Honest limits
Chinese grading is a sentence-length approximation without dictionary parsing, English syllable counts are heuristic, and mixed-language passages are graded as Chinese. Grades describe difficulty, never quality.
Privacy
Privacy is straightforward here: scoring happens in the browser on every keystroke, and your text is never sent to a server.
Last updated · 2026-09-01
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