Flesch-Kincaid Readability Score Calculator
ANA›Life Services Authority›National Calculator Authority›Flesch-Kincaid Readability Score Calculator
.calc-container { max-width: 640px; margin: 2rem 0; padding: 1.5rem; background: #fff; border: 1px solid #ddd; border-radius: 8px; box-shadow: 0 1px 3px rgba(0,0,0,0.06); font-family: system-ui, -apple-system, sans-serif; } .calc-container h3 { font-family: Georgia, serif; font-size: 1.15rem; color: #1a1a1a; margin-bottom: 1rem; padding-bottom: 0.5rem; border-bottom: 2px solid var(--ac, #3d5a80); } .calc-row { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 0.75rem; flex-wrap: wrap; } .calc-row label { min-width: 160px; font-size: 0.9rem; color: #333; font-weight: 500; } .calc-row input[type="number"], .calc-row select { flex: 1; min-width: 120px; max-width: 200px; padding: 0.5rem 0.6rem; border: 1px solid #ccc; border-radius: 4px; font-size: 0.9rem; font-family: system-ui, sans-serif; color: #1a1a1a; background: #fafaf8; } .calc-row input:focus, .calc-row select:focus { outline: none; border-color: var(--ac, #3d5a80); box-shadow: 0 0 0 2px rgba(26,74,138,0.12); } .calc-row .unit { font-size: 0.82rem; color: #888; min-width: 30px; } .calc-btn { display: inline-block; margin-top: 0.5rem; padding: 0.55rem 1.5rem; background: var(--ac, #3d5a80); color: #fff; border: none; border-radius: 4px; font-size: 0.9rem; font-weight: 600; cursor: pointer; font-family: system-ui, sans-serif; } .calc-btn:hover { opacity: 0.9; } .calc-result { margin-top: 1.25rem; padding: 1rem 1.25rem; background: #f0f6fc; border-left: 3px solid var(--ac, #3d5a80); border-radius: 0 6px 6px 0; display: none; } .calc-result.visible { display: block; } .calc-result-label { font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.06em; color: #666; margin-bottom: 0.25rem; } .calc-result-value { font-size: 1.6rem; font-weight: 700; color: var(--ac, #3d5a80); } .calc-result-detail { font-size: 0.85rem; color: #555; margin-top: 0.5rem; line-height: 1.5; } .calc-note { margin-top: 1rem; font-size: 0.8rem; color: #888; font-style: italic; } .calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 0.75rem; margin-top: 0.75rem; } .calc-grid-item { padding: 0.6rem 0.8rem; background: #f8f9fa; border-radius: 4px; border: 1px solid #eee; } .calc-grid-item .label { font-size: 0.75rem; color: #888; text-transform: uppercase; letter-spacing: 0.04em; } .calc-grid-item .value { font-size: 1.1rem; font-weight: 600; color: #1a1a1a; } @media (max-width: 720px) { .calc-row { flex-direction: column; align-items: flex-start; gap: 0.3rem; } .calc-row label { min-width: auto; } .calc-row input[type="number"], .calc-row select { max-width: 100%; width: 100%; } .calc-grid { grid-template-columns: 1fr; } } .calc-chart { margin: 1rem 0; text-align: center; } .calc-chart svg { max-width: 100%; height: auto; } .calc-chart-legend { display: flex; flex-wrap: wrap; justify-content: center; gap: 0.6rem 1.2rem; margin-top: 0.6rem; font-size: 0.8rem; color: #555; } .calc-chart-legend span { display: inline-flex; align-items: center; gap: 0.3rem; } .calc-chart-legend i { display: inline-block; width: 10px; height: 10px; border-radius: 2px; font-style: normal; } .calc-related { max-width: 640px; margin: 2rem 0 1rem; padding: 1.25rem 1.5rem; background: #f8f9fa; border: 1px solid #e8e8e8; border-radius: 8px; } .calc-related h3 { font-family: Georgia, serif; font-size: 1rem; color: #1a1a1a; margin: 0 0 0.75rem; padding-bottom: 0.4rem; border-bottom: 2px solid var(--ac, #3d5a80); } .calc-related-list { list-style: none; padding: 0; margin: 0 0 0.75rem; display: grid; grid-template-columns: 1fr 1fr; gap: 0.4rem 1.5rem; } .calc-related-list li a { font-size: 0.88rem; color: var(--ac, #3d5a80); text-decoration: none; } .calc-related-list li a:hover { text-decoration: underline; } .calc-browse-all { margin: 0.5rem 0 0; font-size: 0.9rem; font-weight: 600; } .calc-browse-all a { color: var(--ac, #3d5a80); text-decoration: none; } .calc-browse-all a:hover { text-decoration: underline; } @media (max-width: 720px) { .calc-related-list { grid-template-columns: 1fr; } }
Flesch-Kincaid Readability Score Calculator
Paste or type any text below to instantly calculate its Flesch Reading Ease score and Flesch-Kincaid Grade Level, helping you understand how easy or difficult the text is to read.
Text Input
Word Count —
Sentence Count —
Syllable Count —
Calculate Readability
Flesch Reading Ease
Flesch-Kincaid Grade Level
Flesch Reading Ease Scale
0 (Very Hard)30507090100 (Very Easy)
function fleCountSyllables(word) { word = word.toLowerCase().replace(/[^a-z]/g, ''); if (word.length === 0) return 0; if (word.length 2 && !'aeiou'.includes(word[word.length - 3])) count++; if (word.match(/[^aeiou]ed$/)) count = Math.max(1, count - 1);
return Math.max(1, count); }
function fleCountWords(text) { var words = text.trim().match(/\b[a-zA-Z'-]+\b/g); return words ? words : []; }
function fleCountSentences(text) { // Split on sentence-ending punctuation var sentences = text.trim().split(/[.!?]+/); // Filter out empty strings sentences = sentences.filter(function(s) { return s.trim().length > 0; }); return Math.max(1, sentences.length); }
function fleGetEaseLabel(score) { if (score >= 90) return { label: "Very Easy", desc: "Easily understood by an average 11-year-old student", color: "#22c55e" }; if (score >= 80) return { label: "Easy", desc: "Conversational English for consumers", color: "#84cc16" }; if (score >= 70) return { label: "Fairly Easy", desc: "Easily understood by 13–15 year old students", color: "#a3e635" }; if (score >= 60) return { label: "Standard", desc: "Easily understood by 13–15 year old students", color: "#eab308" }; if (score >= 50) return { label: "Fairly Difficult", desc: "Fairly difficult to read", color: "#f97316" }; if (score >= 30) return { label: "Difficult", desc: "Best understood by college graduates", color: "#ef4444" }; return { label: "Very Confusing", desc: "Best understood by university graduates", color: "#dc2626" }; }
function fleGetGradeLabel(grade) { if (grade
#### Formulas
Flesch Reading Ease (FRE):
FRE = 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words)
Flesch-Kincaid Grade Level (FKGL):
FKGL = 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59
Reading Ease Score Interpretation:
ScoreDifficultyTypical Reader 90–100Very Easy5th grade 80–90Easy6th grade 70–80Fairly Easy7th grade 60–70Standard8th–9th grade 50–60Fairly Difficult10th–12th grade 30–50DifficultCollege level 0–30Very ConfusingCollege graduate
#### Assumptions & References
- Sentences are detected by splitting on ., !, and ? punctuation marks.
- The Flesch Reading Ease formula was developed by Rudolf Flesch and published in The Art of Readable Writing (1949).
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