Readability Score Calculator
Practice and calculate readability score with our free tool. Includes worked examples, visual aids, and learning resources.
Reviewed by Daniel Agrici, Founder & Lead Developer
Formula
Flesch Reading Ease = 206.835 − 1.015 × (words / sentences) − 84.6 × (syllables / words)
The formula scores text from roughly 0 to 100 using two inputs: average sentence length (words per sentence) and average word complexity (syllables per word). Longer sentences and longer words both push the score down, since both increase how much a reader must hold in working memory to parse a sentence. A companion formula, Flesch-Kincaid Grade Level, converts the same two inputs into a US school grade level instead of a 0-100 score, which is why this tool reports both figures together — one for a quick difficulty label, one for a concrete target grade level when writing for students, patients, or general web readers.
Worked Examples
Example 1: Simple text
Problem:\"The cat sat on the mat.\"
Solution:Short words, simple sentence → Flesch ~100
Result:~100 (Very Easy)
Example 2: Academic Passage Aimed at a General Audience
Problem:A nonprofit rewrites a grant report sentence from \"Utilization of the intervention resulted in a statistically significant amelioration of participant outcomes\" to \"Using the program helped participants get better results.\" How does the readability score change?
Solution:Original: long sentence, multi-syllable words (utilization, amelioration) → Flesch score roughly in the 0-20 range (Very Difficult / graduate level)\nRewrite: short sentence, one- and two-syllable words → Flesch score roughly 70-80 (Easy / 7th-8th grade level)
Result:The rewrite moves the passage from graduate reading level to general-public reading level without changing its meaning — exactly the gap this calculator is built to surface before publishing patient materials, grant reports, or public-facing content.
Frequently Asked Questions
What is the Flesch-Kincaid readability score?
The Flesch-Kincaid Reading Ease score (0–100) measures how easy text is to read — higher scores mean easier reading. The grade-level variant estimates the US school grade needed to understand the text. Scores are calculated from average sentence length and average syllables per word. General audiences need a score of 60–70 (8th–9th grade level).
How do I improve the readability score of my writing?
To improve readability: use shorter sentences (aim for 15–20 words average), choose simpler words (use 'use' not 'utilize'), break up long paragraphs, use subheadings and bullet points, avoid jargon unless writing for specialists, and use active voice. Hemingway App and similar tools provide real-time readability feedback as you write.
References
Reviewed by Daniel Agrici, Founder & Lead Developer · Editorial policy