About the Readability Score Calculator
This readability score calculator analyses text as you type and reports two widely used measures: the Flesch Reading Ease score, running from 0 to 100 with higher meaning easier to read, and the Flesch-Kincaid Grade Level, expressed as a US school grade. Both are calculated from the same two underlying measurements — average sentence length and average syllables per word — which together predict how demanding a piece of writing is to read.
How to use the Readability Score Calculator
- 1
Paste or type the text you want to check into the box.
- 2
Read the Flesch Reading Ease score and its plain-English band, from very easy to very difficult.
- 3
Check the Flesch-Kincaid Grade Level for the equivalent US school grade.
- 4
Use the word, sentence and syllable averages underneath to see which is driving the score.
What people use it for
Writing for a general audience
Check that a blog post, help article or marketing page sits in an accessible readability range rather than accidentally reading like an academic paper.
Meeting a plain-language requirement
Government and healthcare guidelines often specify a target reading grade level. Check a document against that requirement before publishing.
Simplifying dense writing
Identify overly long sentences and complex vocabulary by watching the score change as a passage is edited down.
How the Flesch formulas actually work
Flesch Reading Ease is calculated as 206.835 minus 1.015 times the average number of words per sentence, minus 84.6 times the average number of syllables per word. Longer sentences and longer, more syllable-heavy words both push the score down, meaning the text is judged as harder to read. The Flesch-Kincaid Grade Level rescales the same two inputs onto the US school grade system instead, using different coefficients, so a score of 8 suggests the text is readable by someone at an eighth-grade level.
Why word count alone can't measure readability
Two passages with the exact same number of words can read completely differently depending on sentence structure and vocabulary — one written in short, plain sentences with common words, another in long, clause-heavy sentences with technical vocabulary. Readability formulas exist precisely because raw length says nothing about how much cognitive effort a reader actually needs; sentence length and word complexity are the two factors that consistently predict reading difficulty across a huge range of tested texts.
Tips
- Aim for a Flesch Reading Ease score of 60 or above for general web content — that corresponds to plain English most adults read comfortably.
- Breaking up long sentences is usually the fastest way to raise a low score, since sentence length has a larger effect than word choice alone.
- A very high score isn't always the goal — technical documentation for an expert audience is expected to sit lower, and that's appropriate for its readers.