Readability Checker Text
Flesch reading ease, grade level and the numbers behind them.
Readability Checker is a free online tool that flesch reading ease, grade level and the numbers behind them. It runs entirely in your web browser using plain JavaScript, so files are processed on your own device and never uploaded to a server. There is no sign-up, no file size limit imposed by the site, no watermark and no paid tier.
- Price
- Free — no account, no quota, no watermark
- Category
- Text
- Where it runs
- In your browser, on your device
- Files uploaded
- None
- Technology
- plain JavaScript
- Settings
- None — it just works
- Works offline
- Yes, after the first visit
About Readability Checker
This reports Flesch Reading Ease, which scores text from 0 to 100 on a formula combining average sentence length and average syllables per word. Plain-language guidance in UK and US government writing generally targets 60 or above, roughly a 13-to-15-year-old reading level. The formula was published by Rudolf Flesch in 1948 and is still what most style checkers use.
How to use it
- Paste or type your text. Every figure recalculates on each keystroke.
- Use the sample button to see what the numbers look like on real prose.
Under the hood
| Runs on | plain JavaScript — runs the whole thing |
Questions
What score should I aim for?
60–70 for general audiences — that is the band most newspapers occupy. Above 80 reads as simple and direct; below 30 is dense academic or legal prose. Technical documentation typically lands at 40–50 and that is appropriate.
How is syllable counting done?
By a vowel-group heuristic with corrections for silent E and common endings. It is accurate to a few percent across a paragraph, which is enough for the score, but it will misjudge individual unusual words.