Health literacy - Use a readability tool to prioritise content

If you have a lot of content, one way to decide what to focus on is to use a readability tool.

It cannot tell you how easy your content is to understand. But it can show if the language might be too complex for many people.

Use the SMOG calculator

We use a tool called the SMOG calculator to measure readability.

This uses the number of sentences and complex words (3 or more syllables) to give a readability score.

Before using the SMOG calculator:

  • add full stops to the end of every heading and bullet point
  • if the title of the content includes a word with 3 or more syllables (for example, "paracetamol"), remove this word from the text

This will help you get more accurate scores when comparing content.

Prioritise content with a score over 14

The lower the score, the fewer complex words you're using.

A score higher than 14 means most users might struggle with the language in your content.

What SMOG readability scores mean
SMOG readability score UK adults at this level Typical literacy skills at this level
7 to 9 93% understands short, simple content on familiar topics from familiar sources
10 to 11 76% understands short, simple content from a range of everyday sources (like newspapers)
12 to 13 51% understands simple content of varying lengths on a variety of topics
14 to 16 22% understands content of varying complexity, from a range of sources
17 or more Less than 22% able to obtain, interpret and evaluate complex content

Read our page about health literacy to see it's important to create content that's simple to read.

Do not rely on readability scores alone

A readability score under 14 does not prove your content is useful for your users. It just means you're not using lots of complex words.

Readability scores do not tell you if your content is easy to understand or act on.

You can only find out how well your content works by testing it with users.

Improve your content

When you've identified content with a high readability score, look to improve it using:

Get in touch

If you’ve got a question about the NHS digital service manual or want to feedback, get in touch.

Updated: July 2019