10 free readability calculators

Test your clarity with these cool tools

WordsCount’s SMOG Calculator measures the readability of your copy based on sentence length and syllable length and delivers the grade level a reader would need to have achieved to easily read your copy.

Does not compute Make sure your message is readable with any of these eight readability calculators. Image by Cathryn Lavery

8 more free online calculators

You can also run other readability tests on your copy online with:

  • Edit Central’s readability calculators. Run the Flesch Reading Ease, Automated Readability Index, Flesch-Kincaid Grade Level, Coleman-Liau Index, Gunning Fog index and the SMOG Index on your copy.
  • Gunning Fog Index calculator. Cut and paste your copy to learn the reading grade level of your piece.
  • Juicy Studios online readability tester. Plug in your URL, and run your webpage through the Gunning Fog, Flesch Reading Ease and Flesch-Kincaid Grade Level indexes.
  • OKAPI! Run Spache (grades 1 through 3) or Dale-Chall (grades 4 and up) on your copy.
  • Readability analyzer. This tool not only analyzes readability, but also gives you different ways to dig into your message, from paragraph-by-paragraph level readability to Difficult and Extraneous Word Finder to Passive Voice Detector to Site Thin Content Checker and more.
  • Readability calculator. This free online tool calculates the Coleman Liau index, Flesch-Kincaid Grade Level, Automated Readability Index and SMOG.
  • Readability Test Tool. Run your copy through the Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog, Coleman-Liau Index and Automated Readability Index (ARI).
  • STORYtoolz. Run seven readability tests — the Automated Readability Index, Coleman-Liau, Laesbarhedsindex (LIX), Flesch-Kincaid Grade Level, Flesch Reading Ease, Gunning Fog index and SMOG (Simple Measure of Gobbledygook) — on your copy.

Plus one that’s on your computer

You can also test readability through Microsoft Word’s readability statistics.

Turn it on Once you check ‘Show readability statistics’ in Microsoft Word, you’ll get lots of information about how readable your copy is every time you run spelling and grammar check.

Mac users: Go to Word > Preferences > Spelling and Grammar > Click “Show readability statistics” box.

PC users: Go to File > Options > Proofing > Click “Show readability statistics” box.

Once you’ve turned it on, every time you run spelling and grammar check, you’ll get a box with lots of information about your copy.

Caveat: In older versions of Office, the Flesch Reading Ease formula doesn’t report scores lower than zero, and the Flesch-Kincaid grade level doesn’t report scores higher than 12. With Office 2003, Microsoft fixed the grade level formula but not the reading ease formula.

Both remain defective in Mac versions of the software.


A version of this post was previously published on Wylie Communications.

Ann Wylie is president of Wylie Communications, a writing training and consulting firm. She works with communicators who want to reach more readers and with organizations that want to get the word out. Keep up with Wylie’s Writing Tips via her free ezine. Check out her upcoming writing workshops.