Flesch-Kincaid Calculator

Calculate Flesch Reading Ease and Flesch-Kincaid Grade Level, then inspect the sentence and syllable patterns driving the result.

Flesch Reading Easeclassic 206.835-based ease score

FK Grade LevelU.S. school-grade estimate

Sentence diagnosislong / complex sentence queue

Cross-check formulasFog · SMOG · CLI · ARI

—Flesch Reading Ease

—Flesch-Kincaid grade

0Words

0Est. syllables

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Reading Ease = 206.835 − 1.015 × words/sentences − 84.6 × syllables/words
Grade Level = 0.39 × words/sentences + 11.8 × syllables/words − 15.59

Readability diagnosis workbench

See why the Flesch-Kincaid score moved

Keep Flesch Reading Ease and FK Grade Level as the primary results, then inspect sentence length, estimated syllable density, 3+ syllable words, and supporting readability formulas.

Flesch first · diagnostics second

Target grade

—Flesch ease

—FK grade

—Gunning Fog

—SMOG

—Coleman-Liau

—ARI

—Words / sentence

—Est. syllables / word

—3+ syllable words

—Target-grade gap

Sentence difficulty map

#	Words	3+ syl.	Ease	Flag	Sentence

3+ syllable words

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Copyable readability audit

Analyzing the sample text…

Formula boundary. Flesch-Kincaid, Fog, SMOG, Coleman-Liau, and ARI are readability heuristics, not proof that a particular reader will understand the text. Browser-local syllable estimates can be distorted by names, abbreviations, formulas, code, and non-English text. SMOG is especially sensitive to short samples and is commonly interpreted with longer passages.

Core counting & writing metrics

Start with the broad counter that matches the question, then move to focused frequency, reading-time or syllable analysis. Specialist readability, repetition and writing-goal tools remain available from the full hub.

All 28 text analysis tools

Word CounterWords, characters, structure & reading time Character CounterCharacters, code points & limits Sentence CounterSentence count & average length Paragraph CounterParagraph blocks, words & lines Line CounterLogical, empty & non-empty lines Word FrequencyTop terms & vocabulary diversity Reading TimeWords to minutes at a chosen WPM Syllable CounterSyllable estimate & density

Estimate English readability

The classic Flesch Reading Ease and Flesch-Kincaid Grade Level formulas use sentence length and syllables per word. Higher Reading Ease generally means easier prose, while Grade Level approximates a U.S. school grade.

Heuristic syllables

Browser-local syllable estimation is approximate. Names, abbreviations, code, formulas, and non-English text can distort the score, so treat the result as a writing signal rather than a formal assessment.