Reading level checker: the score, and the sentences behind it.

The score is made of two numbers

Both Flesch formulas use only two measurements: how many words per sentence, and how many syllables per word. Everything else about your writing is invisible to them. That is their weakness, since a string of short nonsense sentences scores as very readable. It is also why they are useful: the two inputs are the two things you can change mechanically.

Of the two, sentence length has more leverage in practice. Vocabulary is often fixed by the subject: a page about “authentication” has to say authentication. Sentence length is almost always a choice. That is why this checker lists your long sentences, longest first, rather than just printing a grade.

How to edit toward a band

1. Paste the draft and note the Flesch-Kincaid grade and average sentence length.
2. Split the three longest sentences in the list. Most long sentences are two or three ideas joined by commas or “and”; they come apart cleanly.
3. Re-check. If the grade is in the band your readers need, stop.
4. Only then look at long words, and replace the ones that have a plain equivalent that means the same thing. Keep the ones that are the precise term.

What readability does not measure

A readable page can still be wrong, thin or off-topic. Readability is a finishing check, run once a draft covers what it should. The word counter gives the broader picture of a draft’s length and reading time, and a content brief is where you decide what the draft should cover in the first place.