Over 84+ Rix analyses

Rix Readability Calculator

Simplified Lix variant with grade-level output. Long words (7+ letters) per sentence. Developed by Jonathan Anderson for teachers and librarians.

Rix Score

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Interpretation

Long word count (>6 letters)

Sentence count

Word count

Why Use Our Rix Readability Calculator?

Our Rix Readability Calculator measures text difficulty using long words (7+ letters) per sentence. Developed by Jonathan Anderson as a simplified Lix variant with grade-level output. Ideal for teachers, librarians, and educational materials.

Simplified Lix

Rix = long words / sentences. Simpler than Lix, with grade-level interpretation. Correlates almost perfectly with Lix.

Grade-Level Output

Anderson converted Rix to grade levels for teachers and librarians. Useful for materials spanning grades 3 through 12.

Language-Neutral

Uses only letter count (7+ letters)—no syllable analysis. Works well for Danish, Swedish, Norwegian, Dutch, and English.

How the Rix Readability Calculator Works

Our tool uses the Rix formula (Anderson) to measure readability

Paste Your Text

Paste your content into the text area. Rix works with any length of text—from short paragraphs to full documents.

Instant Rix Score

We count long words (7+ letters) and sentences, then apply: Rix = long words / sentences.

Clear Interpretation

Get a grade-level interpretation: from below 3rd grade through college level.

Ready to Check Your Rix Score?

Measure the readability of your text with our free Rix Readability Calculator. Simplified Lix with grade-level output. Aim for ~8th grade for public writing.

Calculate Rix

Frequently Asked Questions

What is the Rix readability formula?

Rix is a simplified readability formula developed by Jonathan Anderson, an Australian teacher, as a variant of Lix. It converts Lix to a grade-level format that teachers and librarians find practical. Rix uses only long words (7+ letters) and sentences—no syllable counting. It correlates highly with Lix and is useful for grades 3 through 12.

How is the Rix score calculated?

Rix = long words / sentences. Long words are words with more than 6 letters (7+ letters), counted after stripping punctuation. We divide the number of long words by the number of sentences. Lower scores indicate easier text; higher scores indicate more difficult text.

What is a good Rix score?

For public writing, aim for a Rix score that corresponds to about 8th grade level (typically a score around 3–5). Lower Rix scores indicate text readable by lower grade levels. Rix is useful for materials spanning grades 3 through 12.

How does Rix differ from Lix and Flesch-Kincaid?

Rix is a simplified Lix: Rix = long words / sentences, while Lix uses (words/sentences) + (long words × 100 / words). Rix produces a simpler ratio that Anderson converted to grade levels. Unlike Flesch-Kincaid, Rix uses only letter count—no syllable analysis—making it language-neutral.

When should I use the Rix readability formula?

Use Rix when you need a simple, grade-level readability measure for educational materials, when categorising books for teachers or librarians, or when you want a formula that correlates with Lix but is easier to interpret. It works well across multiple languages including Danish, Swedish, Norwegian, and Dutch.

How long should my text be for a reliable Rix score?

Use at least 100 words for stable results. Longer passages give a more representative grade. Very short samples can be skewed by a few long words or sentences.

What is the Rix Readability Formula?

Rix is a simplified readability formula developed by Jonathan Anderson, an Australian teacher, as a variant of Lix. Anderson wanted to convert Lix to a grade-level format that teachers and librarians find practical. Rix = long words / sentences, where long words have 7+ letters.

Rix correlates almost perfectly with Lix but is simpler to calculate and interpret. It uses only letter counting—no syllable analysis—making it language-neutral and effective for multiple languages.

How the Rix Formula Works

Rix is calculated as (long words ÷ sentences), where long words are words with 7 or more letters. The result is then converted to a U.S. grade level. So it is a very simple measure: how many long words per sentence. Anderson developed it so teachers and librarians could get a quick grade-level estimate without the full Lix calculation. Like Lix, Rix is language-neutral because it uses only letter count.

When to Use Rix

Use Rix when you want a simple, language-neutral grade level from long words per sentence. It is handy for quick checks and for non-English or multilingual text. If your guideline specifies Flesch-Kincaid or SMOG for English, use those; otherwise Rix is a good option when you want a grade level without syllable analysis. To compare with all nine formulas, use our Combined Readability Checker.

Industry Guidelines and Targets

Rix is less often explicitly mandated than Flesch-Kincaid or SMOG, but the same general targets apply: 8th grade or lower for broad audiences. Use the calculator to see where your text falls. Because Rix uses only long words (7+ letters) per sentence, reducing the number of long words or shortening sentences will lower the grade.

How to Improve Your Rix Score

To lower the Rix grade, use fewer long words (7+ letters) and shorter sentences. Replace long words with shorter synonyms. Break long sentences into two or three shorter ones. The formula is simple: long words per sentence. So any reduction in long words or increase in sentence count (shorter sentences) will help. Re-run your text after revisions to see the new grade.

How to Use This Calculator

Paste your text into the box at the top and click analyze. You will see your Rix score and a grade-level interpretation. No signup required. For stable results use at least 100 words. To see how the same text scores on Lix, Flesch-Kincaid, SMOG, and six other formulas, use the Combined Readability Checker.

Rix Readability Calculator