k-o.pro

Readability Checker

Paste any text and get Flesch Reading Ease, Gunning Fog Index, and grade-level scores in one click.

Results update automatically as you type.

How it works

  • • Flesch Reading Ease — 0 to 100. Above 60 is readable for most adults
  • • FK Grade Level — US school grade needed to understand the text
  • • Results update automatically as you type — no submit needed

What gets measured

Four scores, each measuring a different dimension of complexity:

  • Flesch Reading Ease — 0 to 100. Above 60 is readable for most adults
  • Flesch-Kincaid Grade Level — US school grade needed to understand the text
  • Gunning Fog Index — combines sentence length and complex word count
  • Average sentence length and syllables per word

The target most SEO content misses

Flesch Reading Ease below 30 is classified as "Very Confusing" — the level of academic research papers. Most top-ranking informational content scores 60–70.

How to use it

  1. Paste your draft or a section of it into the text area
  2. Check the Flesch Reading Ease score first — it's the most actionable
  3. If the score is low: break long sentences, replace multi-syllable words where shorter ones work
  4. Paste again after editing to confirm the improvement

Target scores by content type

General SEO content: aim for Flesch 60–70, grade level 8–9. Product documentation: 50–60 is acceptable. Technical developer docs: 40–50 is fine if the audience expects it. Anything below 30 loses most readers before they finish the page.

Frequently asked questions

Is this readability checker free?

Yes, free and no signup. Paste text and get the scores instantly.

What readability score should I aim for?

For general web content, a Flesch Reading Ease in the 60 to 70 range, roughly grade 7 to 9, works well.

Does readability affect SEO?

Not as a direct ranking factor, but it improves engagement and comprehension, which support rankings indirectly.

Related tools: keyword density checker and meta tags analyzer. Background reading: balancing SEO and natural content.