Readability Checker

Check your text's Flesch Reading Ease score and grade level, with sentences over 25 words flagged for revision — the standard readability formulas used by editors, writers, and content teams.

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Uses the standard Flesch Reading Ease and Flesch-Kincaid Grade Level formulas, based on a heuristic syllable count (the same approach used by most readability tools). Treat scores as a useful estimate, not an exact measurement.

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Why use Readability Checker?

Readability formulas reduce "how easy is this to read" to two measurable factors: how long your sentences are, and how complex your words are (approximated by syllable count). Neither is a perfect proxy for actual clarity — a short, jargon-dense sentence can still confuse a reader — but decades of use across publishing, education, and plain-language writing have shown they correlate well enough with real reading difficulty to be genuinely useful. The Flesch Reading Ease score and its companion Flesch-Kincaid Grade Level are the two most widely used versions of this idea, and this tool computes both live as you type, alongside a list of any sentences running over 25 words — a length where readers reliably start losing track of the sentence's structure, regardless of how simple the individual words are.

Key benefits

Standard Flesch Reading Ease and Flesch-Kincaid Grade Level formulas
Long sentences flagged automatically
Live results as you type
Free, no account required

Features

Flesch Reading Ease score (0-100)
Flesch-Kincaid grade level
Complex-word and long-sentence detection

Popular use cases

Checking a blog post or article's reading level before publishing
Simplifying technical writing for a general audience
Meeting a required readability target for a style guide
Comparing draft revisions to see if simplification actually helped

How to use Readability Checker

1
Paste your text
A paragraph, article, or full document.
2
Read your scores
Flesch Reading Ease, grade level, and sentence/word stats update live.
3
Review flagged sentences
Sentences over 25 words are listed as candidates for splitting.

Frequently asked questions

What is a good Flesch Reading Ease score?

60-70 is considered 'standard,' comfortable for most general audiences (roughly 8th-9th grade reading level). Higher scores (80+) suit a broad, casual audience; lower scores (30-50) are typical for academic or technical writing where some complexity is expected.

How is the score calculated?

From average sentence length (words per sentence) and average word complexity (syllables per word) — the Flesch Reading Ease formula is 206.835 − 1.015 × (words/sentence) − 84.6 × (syllables/word). Shorter sentences and simpler words push the score higher (easier to read).

How accurate is the syllable count?

It uses a heuristic vowel-group counting method, the same approach used by virtually every free readability tool, since true syllable counting requires a full pronunciation dictionary. It's accurate for the large majority of common English words but can be off for unusual or foreign-derived words.

Why does a long sentence hurt readability even with simple words?

The Flesch formula weighs sentence length directly — long sentences require the reader to hold more in working memory before the meaning resolves, which is why sentences over roughly 25 words are flagged separately as a concrete place to simplify.

Last reviewed: September 2026

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