How to test readability

Use the Flesch Reading Ease Scale

tape measure

The Flesch Reading Ease Scale is an internationally recognised test. It uses a simple formula to measure a document’s readability and gives it a score of between 0 and 100. A high score indicates that the text is easy to read.

For example, Time magazine is in the 50s and the Harvard Law Review is in the 30s. In some US states, all customer materials from insurance companies must have a Flesch score of 45 or over.

Rudolf Flesch, who created the system, warned: ‘Some readers, I am afraid, will expect a magic formula for good writing and will be disappointed with my simple yardstick. Others, with a passion for accuracy, will wallow in the little rules and computations but lose sight of the principles of plain English.

‘What I hope for are readers who won’t take the formula too seriously and won’t expect from it more than a rough estimate.’

The system calculates the average sentence length and the average number of syllables per word. This means that a lot of long sentences or long words will reduce your score. However, there are many longer words we use every day that won’t provide readers with problems (e.g. calendar, entertainment, effectively and maintenance).

Flesch scoreReadability level
90-100Very easy (easily understood by an average 11-year-old)
70-79Fairly easy
60-69Standard (easily understood by 13- to 15-year-olds)
50-59Fairly difficult
0-29Very difficult (suitable for university graduates)


Capture Flesch reader after red ring

Version 1 – Score 36.2

The Public Sector needs to adopt the newborn Conversation Society soon as reflected in Social Media.  Those that don’t they will find themselves disconnected from their citizens, employees and 21st century value creation.

Capture Flesch before red ring

Version 2 – Score 48.5

The public sector needs to start using social media if it wants to communicate effectively with staff and the public.

How to set it up in MS Word

1. Open a Word document and then:

  • Version 2007: Click the Office button in the top left and then click Word Options.
  • Version 2010 onwards: Click File and scroll down to Options

2.  Click Proofing.

3.  Under When correcting spelling and grammar in Word, make sure Check grammar with spelling is selected.

4.  Select Show readability statistics.

      You are now set up. Next time you spell check a Word document, you’ll see the readability statistics.

How to use a readability test without MS Word

If you don’t have MS Word, you can use readability tests online.

For more information

Read Wikipedia on readability tests.

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