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Dale-Chall ReadabilityCalculate Dale-Chall readability score using familiar word analysis.

Dale-Chall Readability illustration
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Dale-Chall Readability

Calculate Dale-Chall readability score using familiar word analysis.

How to Use
1

Paste Text

Enter text to analyze for vocabulary difficulty.

2

View Score

Get the Dale-Chall score and grade level.

3

Review Words

See which words are not on the familiar word list.

What Is Dale-Chall Readability?

The Dale-Chall Readability Score uses a list of ~3,000 words that 80% of 4th graders understand. Words not on this list are "difficult." Formula: 0.1579*(% difficult words) + 0.0496*(avg sentence length), plus 3.6365 if difficult words exceed 5%. This vocabulary-based approach catches complexity that sentence-length formulas miss. Validated against actual comprehension data, making it one of the most reliable readability measures.

Why Use Our Dale-Chall Readability?

  • Identifies specific difficult words to replace
  • Vocabulary-based analysis catches complexity others miss
  • Validated against comprehension data
  • Actionable word-level feedback
  • Widely used in education and publishing

Common Use Cases

Textbook Publishing

Match materials to grade levels based on vocabulary.

Plain Language

Identify unfamiliar vocabulary in government documents.

ESL Content

Create materials with familiar vocabulary.

Technical Writing

Identify terms to define or replace.

Technical Guide

PDW = % difficult words, ASL = avg sentence length. Score = 0.1579*PDW + 0.0496*ASL + 3.6365 (if PDW > 5%). Score ranges: <=4.9 = grade 4, 5-5.9 = grades 5-6, 6-6.9 = grades 7-8, 7-7.9 = grades 9-10, 8-8.9 = grades 11-12, 9+ = college.

Tips & Best Practices

  • 1
    The 5% difficult word threshold causes a significant score jump
  • 2
    The difficult word list shows exactly what to simplify
  • 3
    Aim for Dale-Chall below 6.0 for web content
  • 4
    Combine with sentence-length formulas for best results

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Frequently Asked Questions

QHow many words on the familiar list?
About 3,000 words that 80% of 4th graders understand.
QWhy the score jump at 5%?
Adding 3.6365 reflects the sharp comprehension drop when more than 1 in 20 words is unfamiliar.
QHow does it compare to Flesch-Kincaid?
Dale-Chall uses word familiarity, FK uses syllables. Dale-Chall is often considered more reliable.
QAre proper nouns difficult?
Proper nouns not on the list are counted as difficult.
QIs the 1995 revision different?
Updated word list, same core formula.

About Dale-Chall Readability

Dale-Chall Readability is a free online tool from FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration required. No ads. Just fast, reliable tools.