Flesch-Kincaid Readability Analyser
Paste any text to get its Flesch Reading Ease score, Flesch-Kincaid Grade Level, and sentence/word/syllable counts — calculated entirely in your browser.
35 words · 3 sentences
Flesch-Kincaid Grade Level
9.2
Roughly a 9th-grade reading level
Flesch Reading Ease
50.0
Difficult
Avg. words per sentence
11.7
Avg. syllables per word
1.7
Syllable counts use a standard vowel-group heuristic, not a dictionary lookup, so counts can be off by one on unusual words — treat the scores as a useful estimate, not an exact measurement.
About this tool
How to use it
- Paste or type the text you want to check into the text box.
- Press Analyze Readability, or just keep typing — the score updates live.
- Read the Flesch-Kincaid Grade Level as the headline number: it estimates the US school grade a reader would need to follow the text easily.
- Check the Flesch Reading Ease score and its label alongside it for the more traditional 0–100 readability scale.
- Use the word/sentence/syllable counts and the two averages to see what's actually driving the score — long sentences, long words, or both.
Why it matters
Both scores come from the same two ingredients — average sentence length and average syllables per word — so a text scores harder either by using longer sentences or longer words, and often both. Knowing which one is driving a high grade level tells you what to actually fix: trim sentences, or swap in shorter words, rather than guessing.
When to use it
Useful before publishing anything meant for a general audience — a support article, a public notice, a children's book manuscript — where a grade-level target is part of the brief. Also useful for comparing two drafts of the same passage to see whether an edit actually made it easier to read, rather than just feeling shorter.
Good to know
Syllable counts use a standard vowel-group heuristic (count runs of vowels, adjusting for common silent endings), not a dictionary lookup, so an unusual or compound word can be off by one syllable — this is the same approach most readability tools use, and it's accurate enough for the aggregate score even when individual word counts aren't perfect. Both formulas (Flesch Reading Ease and Flesch-Kincaid Grade Level) are the original published formulas from Rudolf Flesch (1948) and J. Peter Kincaid et al. (1975); neither formula accounts for meaning, structure, or whether the content is actually true or well-organized — a grammatically simple sentence about a complex topic can still score 'easy' while being hard to actually understand.
Common questions
What's the difference between Flesch Reading Ease and Flesch-Kincaid Grade Level?
They're calculated from the same two inputs — words per sentence and syllables per word — but scaled differently. Reading Ease runs roughly 0–100 where higher means easier to read; Grade Level maps to a US school grade, where higher means harder. A text can be described by either; most style guides for general audiences target a Reading Ease in the 60s–70s or a Grade Level around 7–9.
How accurate is the syllable count?
It's a heuristic based on counting vowel-sound groups in each word, not a dictionary of verified pronunciations, so it can occasionally miscount an unusual word by one syllable. Across a full paragraph these small errors mostly average out, so the overall score stays a reasonable estimate even when a single word's count is off.
Where do these formulas come from?
Flesch Reading Ease was published by Rudolf Flesch in 1948; the Flesch-Kincaid Grade Level formula was derived from it by J. Peter Kincaid and colleagues in 1975 for the US Navy, to grade the reading difficulty of technical manuals. Both are long-published, fixed formulas — this tool applies them exactly, it doesn't estimate or approximate the coefficients.
Why does my score seem too high or too low for how the text reads?
These formulas only measure sentence length and word length — they say nothing about vocabulary familiarity, sentence structure complexity, or whether ideas are logically ordered. A text full of short, familiar words can still score 'easy' while being conceptually dense, and a text with a few long proper nouns (names, places) can score harder than it actually reads.
What should I do if my grade level is higher than my target audience?
Split long sentences into two, and look for opportunities to swap multi-syllable words for shorter, more common ones — both directly lower the score. Re-run the analysis after editing to see the effect of each change.