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Free Readability Checker

Check the readability of any text. The Flesch-Kincaid grade level, reading ease and sentence length are measured in your browser, and the suggestions to make the text easier to read come from the AI.

Built for bloggers, marketers and SEOs.

What this analyzer measures

Paste any text (a draft blog post, a landing page, an email). Your browser measures the Flesch-Kincaid grade level, reading ease and sentence lengths, and the AI flags the longest and most complex sentences and suggests rewrites you can copy directly.

How to use the results

  1. Check the grade level first. Above grade 10 is a warning sign for general-audience content.
  2. Look at the long-sentence list. Splitting just three or four long sentences usually moves the score significantly.
  3. Use Polish in KoalaWriter to apply readability improvements across an entire article in one click. See the Polish feature page.

Frequently asked questions

What reading grade level should I target?

Most general-audience web content reads best at grade levels 6 to 9. Technical or B2B content can go higher (10 to 12). If you're writing for a broad consumer audience, anything above grade 10 starts to hurt time-on-page and conversion.

What is the Flesch Reading Ease score?

It's a 0 to 100 score where higher means easier. 90 to 100 is very easy, 80 to 90 easy, 70 to 80 fairly easy, 60 to 70 plain English (most blog posts should land at 60 or above), 50 to 60 fairly difficult, 30 to 50 difficult, and under 30 very difficult, the range of academic papers and legal text.

Why does sentence length matter?

Long sentences force readers to hold more context in working memory. As average sentence length climbs past 20 words, comprehension and engagement drop sharply. Splitting long sentences is the single highest-leverage readability fix.

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