Free Readability Checker (+ Guide)

What is readability?

Readability is how easy a text is to read and understand. A readability score measures it from the text itself: mostly how long the sentences are and how long the words are.

The 6 readability formulas

The first 2 are the ones Microsoft Word shows. The others weigh the same things a little differently, so a text's grades land close together.

What readability score to aim for

It depends on who reads it, but 2 well-known guides agree on the rough range:

• Microsoft Word – most documents should score 60 to 70 on reading ease, and a grade level of about 7.0 to 8.0 (Microsoft Support).
• The NHS – a reading age of 9 to 11, which is about US grade 4 to 6, with sentences of up to 20 words and paragraphs of up to 3 sentences (NHS service manual).

Experts reading about their own field can take more, so pick who it's for above and the checker holds your text to that range.

How to make your writing easier to read

The formulas only count 2 things, sentence length and word length, so those are the 2 levers:

• Split long sentences – keep to 20 words or fewer, one idea per sentence.
• Use the short word – "use" not "utilize", "start" not "commence", "help" not "assist".
• Say who does what – "The team wrote the report", not "The report was written".
• Cut adverbs that add nothing – "very", "really" and "actually" rarely earn their place.
• Keep paragraphs short – 3 sentences or fewer reads well on a phone.

• Writing for the formula, not the reader – short choppy sentences can score well and still read badly
• Swapping every long word – some ideas need their exact term, like "photosynthesis" in a biology post
• Trusting one score – check the marked sentences, since the score is only an average

How to check readability in Microsoft Word

Word has the same 2 Flesch scores built in, shown after a spelling and grammar check (Microsoft Support):

This checker gives you the same 2 scores in your browser, plus 4 more formulas, reading time, and the exact sentences to fix.

Reading time

Reading time uses 238 words a minute for silent reading and 183 for reading aloud. Those are the averages across 190 studies of adult readers of English (Brysbaert, 2019, Journal of Memory and Language).

Who is the readability checker for?

It's for anyone who writes for readers in a hurry:

• Reading level checker – people who need the grade level
• Flesch reading ease calculator – anyone who needs the Flesch score
• Flesch-Kincaid calculator – writers matching a school grade
• How to start a blog – bloggers writing their first posts

The rest of my tools are on the free tools page.