Readability Analyzer (Flesch-Kincaid)

Which scores does it report?

Flesch Reading Ease, Flesch-Kincaid Grade Level, and the Gunning Fog index, alongside the raw counts they are built from: words, sentences and syllables.

How do I read the Flesch Reading Ease number?

Higher is easier. It runs on a scale where roughly 60–70 is plain English suited to a general audience, higher numbers are simpler, and scores below about 30 indicate dense, specialist prose. Unlike the other two it is not a grade level, which is why it moves in the opposite direction.

What do the grade-level scores mean?

Both Flesch-Kincaid and Gunning Fog approximate the years of schooling a reader would need. They disagree slightly by design: Flesch-Kincaid weights syllables per word, while Gunning Fog counts "complex" words — here, any word of three or more syllables.

How are syllables counted?

By a heuristic: it counts vowel groups and then removes a silent trailing "e" only in the vowel-consonant-e pattern, so "make" counts as one while "simple" keeps its final syllable. This is an approximation, not a dictionary lookup, so unusual words and names will sometimes be counted wrong.

Why does my score change so much when I add a full stop?

Because sentence count is a denominator in every one of these formulas. Splitting one long sentence into two immediately lowers the average sentence length and improves every score, without changing a single word. That sensitivity is the honest limitation of readability metrics.

Can I improve the score without improving the writing?

Easily, and that is worth knowing. Chopping sentences arbitrarily and swapping long words for short ones will move the numbers while leaving prose worse — the formulas count syllables and lengths, not clarity, logic or whether the argument makes sense. Use them to catch prose that has drifted dense, not as a target to optimise.

Does it work on languages other than English?

No. The syllable heuristic assumes English vowel patterns and all three formulas were fitted to English text. Scores for other languages will be produced but they will not mean anything.

What counts as a sentence?

A run ending in a full stop, question mark or exclamation mark. Abbreviations, decimals and ellipses can therefore inflate the sentence count, which flatters the score slightly.

Is my text uploaded?

No. The analysis runs entirely in your browser; nothing you paste is transmitted or stored.