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Readability Score Calculator: Flesch, Fog, SMOG and ARI

This free readability calculator measures how hard your text is to read. It reports the Flesch Reading Ease, Flesch-Kincaid grade level, Gunning Fog, SMOG, Coleman-Liau and ARI scores in one go.

By Debmedia Technologies LLP · Kolkata, India · Updated

What Is It and When Do You Need It?

Readability scores estimate how easy a piece of writing is to read. Writers, teachers, marketers and health communicators use them to match text to its audience. Shorter sentences and shorter words give an easier score.

Paste at least a few sentences and read all six scores with a short verdict.

How to Use This Tool

  1. Paste your text.
  2. Press Calculate.
  3. Read the grade level and the Reading Ease score.
  4. Shorten long sentences and words, then check again.

How the Calculation Works

The tool counts words, sentences, letters and estimated syllables. Flesch Reading Ease = 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words). Flesch-Kincaid grade = 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59. Gunning Fog uses the share of words with three or more syllables. Coleman-Liau and ARI use letters per word.

Worked Example

The sentence The cat sat on the mat. has 6 words and 6 syllables in 1 sentence, a Reading Ease of 116 and a grade of about −1.4, which is very easy.

Common Uses

  • Writing for the web and for customers.
  • Checking school and health materials.
  • Editing essays and reports.
  • Matching text to a reading age.

Tips and Common Mistakes

  • Aim for grade 6 to 8 for general readers.
  • Use at least 100 words for a stable result.
  • Short sentences help more than short words.

Next, you may need the reading time calculator, syllable counter, character counter, palindrome checker.

Everything runs in your browser. Nothing you type is uploaded, stored or sent to any outside service.

Frequently Asked Questions

Higher is easier. 60 to 70 is plain English that most adults follow, 80 or more is easy, and below 30 is very hard, as in legal or academic writing.
The Flesch-Kincaid grade estimates the years of US schooling needed to understand the text. Grade 8 means an eighth-grader can follow it.
Each formula uses different measures, such as syllables, long words or letters. Look at the range rather than one number.
It is an estimate using English spelling rules. A few words will be miscounted, but the overall score is reliable for long texts.

Disclaimer: results are calculated in your browser from the numbers you enter. Check important results before you rely on them for money, health, safety or legal decisions.