VerifyWrite

Readability checker

Six readability formulas scored live as you type, the sentences that drag your grade up, and an AI rewrite to the reading level you need.

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Rewrite for a reading level

AI rewrites your text to about the grade you choose, keeping every fact. Useful for parent letters, instructions and web copy. Up to 4,000 characters.

Paste text to see all readability scores update live.

How to lower your reading grade

Every formula here leans on the same two levers, so the fixes are the same:

  1. Split long sentences. Anything over 25 words is a candidate. One idea per sentence.
  2. Swap long words for short ones where meaning allows: “use” for “utilise”, “help” for “facilitate”, “about” for “approximately”.
  3. Cut stacked nouns (“student assessment feedback policy review”) into a phrase with a verb.
  4. Keep necessary terms and explain them once. Formulas punish “photosynthesis” even when it is the right word.

Each formula explained

Every formula has its own calculator page with a slider explainer that shows which input moves the score:

  • Flesch Reading Ease – 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words)
  • Flesch–Kincaid Grade Level – 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59
  • Gunning Fog Index – 0.4 × [(words ÷ sentences) + 100 × (complex words ÷ words)]
  • SMOG Index – 1.043 × √(polysyllables × 30 ÷ sentences) + 3.1291
  • Coleman–Liau Index – 0.0588 × L − 0.296 × S − 15.8 (L = letters per 100 words, S = sentences per 100 words)

The Automated Readability Index (ARI) uses characters per word and words per sentence: 4.71 × (characters ÷ words) + 0.5 × (words ÷ sentences) − 21.43.

Questions people ask

What is a readability score?

A number calculated from surface features of text – usually sentence length and word length – that predicts how hard it is to read. Most formulas express the result as a US school grade.

Which readability formula is best?

None is best for everything. Flesch Reading Ease is the most widely recognised, Flesch–Kincaid is built into Microsoft Word, SMOG is preferred for health information, and Coleman–Liau avoids error-prone syllable counting. Looking at the consensus of several is more reliable than any single one.

What readability level should I aim for?

For the general public, around grade 8 or a Flesch Reading Ease of 60–70. For health and safety information, grade 6–8. For specialist readers, higher is acceptable as long as the writing is clear.

Does the rewrite tool change my meaning?

It is instructed to keep every fact, name and number and add nothing. Always read the result before using it, especially for technical or legal content.

The rest of the kit

Your text follows you between tools, so you can paste once and check everything.