What is readability?

Readability is all about how easy or difficult it is to read something.  

Readability depends on a text’s presentation (such as font choice, spacing or colors) and context (the words and sentences on the page).

Other factors that affect readability include sentence length, sentence structure, and the average syllables per word. These combined factors help assess how well your writing will be understood. 

Readability matters. Writing in a simple and clear style makes it easier for the reader to understand your message. We recommend aiming for a reading age of between age 9 and 15.

Why should I care about readability?

Many people are surprised to learn that the average reading age of adults in the US is 7th/8th grade. That means the average person reading your content has the reading ability normally expected of a 12-14 year old.

And most people don't realize that at least one in ten visitors to a website will be dyslexic. Many more web visitors will have cognitive difficulties or a learning disability.

People also do not read one word at a time. They bounce around, especially online. They anticipate words and fill them in. When you write more, people understand less.

It’s a legal requirement

The Plain Writing Act of 2010 was signed on October 13, 2010. The law requires that federal agencies use clear government communication that the public can understand and use

Executive departments and agencies must:

How do I measure readability?

The Flesch reading ease test measures the readability of a text. It uses two variables to determine the readability score:

  • the average length of your sentences (measured by the number of words)
  • the average number of syllables per word

Then, it gives you a score between 0 and 100. A score of 100 means your copy is very easy to read. And, a score of 0 means your text is very difficult to read.  You can see the exact interpretation of all the scores on the scale in the table below. This is another reason why we recommend a reading age of between 9 and 15 years old.




Very easy to read, easily understood by an average 11-year-old student


Easy to read


Fairly easy to read


Easily understood by 13- to 15-year-old students


Fairly difficult to read


Difficult to read, best understood by college graduates


Very difficult to read, best understood by university graduate

9 top tips for better readability

  1. Use plain English
  2. Nobody’s got time for jargon and unnecessary buzzwords
  3. Get straight to the point. Cut dead wood and waffle
  4. Cut repetitive words
  5. Use bullet point or numbered lists
  6. Address your readers directly - ‘you’ and ‘we’
  7. Make it easy to read - use white space and clear sub headings
  8. Define any acronyms or abbreviations
  9. Keep it short

How long should a sentence be?

25 words is our absolute limit. 

Studies also show that sentences of 11 words are considered easy to read, while those of 21 words are fairly difficult. At 25 words, sentences become difficult, and 29 words or longer, very difficult.

If you write short sentences using plain English, it’ll help more people understand your content.

Long, complicated sentences force users to slow down and work harder to understand what they’re reading. This isn’t something people want to do, even if they’re familiar with the subject or language you’re using.

Our rule of thumb is: If it’s complex, make it simple

How Texthelp can help you master readability

The ReachDeck Editor guides you to create content in line with accessibility best practice. 

It’s a grammar, spelling and readability checker that helps everyone in your organization to create internal and external content that’s easy to understand.

With ReachDeck, you can: 

  • Highlight grammar, spelling and readability errors as you write
  • Write in plain English, identifying reading age, long sentences and jargon words