Home / Readability checker
Readability Grade Level Checker
Paste any passage to see its reading grade level. Four open formulas, counted live in your browser.
How readability formulas work
Readability formulas estimate how hard a text is from sentence length and word length. Longer sentences and longer words push the grade level up. The Flesch-Kincaid grade level is the most widely used.
FK grade = 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59
Reading Ease = 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words)
ARI = 4.71 × (characters ÷ words) + 0.5 × (words ÷ sentences) − 21.43
Coleman-Liau = 0.0588 × L − 0.296 × S − 15.8
For Coleman-Liau, L is letters per 100 words and S is sentences per 100 words. Syllables are counted with a standard vowel-group rule, so expect small differences from other tools.
Flesch Reading Ease scale
| Score | Difficulty | Approximate school level |
|---|---|---|
| 90 to 100 | Very easy | Grade 5 |
| 80 to 89 | Easy | Grade 6 |
| 70 to 79 | Fairly easy | Grade 7 |
| 60 to 69 | Plain English | Grades 8 and 9 |
| 50 to 59 | Fairly difficult | Grades 10 to 12 |
| 30 to 49 | Difficult | College |
| 0 to 29 | Very difficult | College graduate |
How teachers use a readability checker
- Levelling your own passages. Check that a passage you wrote matches the grade on the worksheet.
- Choosing articles. Paste a news story before giving it to a class to see if it needs adapting.
- Simplifying text. Split long sentences and swap long words, then watch the grade drop as you edit.
Formulas cannot judge background knowledge, vocabulary or theme. Use the grade as a first check, then read the text with your students in mind.
Frequently asked questions
How is Flesch-Kincaid grade level calculated?
It uses average sentence length and average syllables per word: 0.39 times words per sentence, plus 11.8 times syllables per word, minus 15.59. The result is a US school grade.
What is a good Flesch Reading Ease score?
Scores run from about 0 to 100, and higher is easier. A score of 60 to 70 is plain English that most 13 to 15 year olds read easily. Early primary texts usually score above 80.
Why do the four formulas give different grades?
Each formula weighs different features. Flesch-Kincaid uses syllables, while ARI and Coleman-Liau count characters. The average is a fair single number, and a spread of more than two grades is a sign to read the passage yourself.
Is this the same as a Lexile measure?
No. Lexile is a proprietary measure from MetaMetrics. This tool uses open, published readability formulas. They are useful for comparing passages but should not be reported as Lexile levels.
Does the checker store my text?
No. All counting happens in your browser. The text is never sent to a server.