LIX Readability Score Calculator Online

LIX Readability Score

LIX (abbreviation of Swedish läsbarhetsindex, meaning "readability index") is a readability measure created by Swedish scholar Carl-Hugo Björnsson in 1968. It was originally designed for Swedish texts but works effectively for many languages because it doesn't rely on syllable counting.

The LIX formula is particularly useful for non-English texts where syllable counting may be inaccurate or culturally inappropriate.

LIX Formula

LIX = (Words / Sentences) + (Words with more than 6 letters × 100 / Total Words)

Or broken down:

• Average Sentence Length (words per sentence)
• Plus: Percentage of long words (words with 7+ letters)

Calculation Steps

1. Count the total number of words in the text
2. Count the number of sentences in the text
3. Count the number of long words (words with more than 6 letters)
4. Calculate average words per sentence (words ÷ sentences)
5. Calculate percentage of long words ((long words × 100) ÷ total words)
6. Add the two values together
7. Round to the nearest whole number (optional)

Score Interpretation

LIX scores typically range from 20 to 60, with the following interpretation:

Strengths

• Language Independent: Works for multiple languages without modification
• No Syllable Counting: Uses letter counting instead, which is more reliable across languages
• Simple to Calculate: Easy to compute manually or automatically
• Culturally Neutral: Doesn't rely on language-specific word lists
• Proven Track Record: Used successfully in Scandinavia since 1968

Limitations

• Long words in some languages may not indicate difficulty
• Doesn't consider vocabulary complexity or familiarity
• May be less accurate for languages with very short or very long average word lengths
• Cannot measure conceptual difficulty or subject matter complexity

Comparison with RIX

LIX has a companion formula called RIX (also created for Swedish):

• RIX = Long words ÷ Sentences (simpler calculation)
• LIX = (Words ÷ Sentences) + (Long words × 100 ÷ Words) (more comprehensive)

LIX provides more nuanced results by including both sentence length and word length in a single score.

Use Cases

The LIX formula is ideal for:

• Multilingual Content: Evaluating readability across different languages
• International Publishing: Creating globally accessible content
• Translation Work: Maintaining readability across language versions
• European Content: Popular in Scandinavian and European markets
• Quick Assessment: Fast readability checks without complex calculations

History

LIX was developed by Carl-Hugo Björnsson and published in his 1968 book "Läsbarhetsindex" (Readability Index). It was specifically created to address the limitations of English-centric formulas that relied on syllable counting, which doesn't work well for Swedish and other languages.

Further Reading

• Lix (readability test) - Wikipedia
• The Lix and Rix Readability Formulas – Readable
• Lix Readability Formula – ReadabilityFormulas.com