Readability checker: reading age and grade level

What are reading age and grade level?

A reading age is the age at which a typical reader could follow a piece of writing. A grade level is the same idea counted in years of school. Both come from counting how long the sentences are and how many syllables the words have. The Flesch-Kincaid formula gives a US school grade. Add five to turn it into an age: grade 6 reads at about age 11.

UK guidance talks in reading ages. Australian guidance talks in school years, such as Year 7, and the web accessibility guidelines in years of school. The checker shows whichever your guidance uses. It also gives the Flesch-Kincaid grade, Flesch reading ease and SMOG, for anyone asked for one of those.

What reading level should you aim for?

UK health writing: the NHS

The NHS service manual says: “We aim for a reading age of 9 to 11 years old.” It adds that some medical information makes that hard, and in that case to “try to make sure that an 11 to 14-year old will understand.” (NHS service manual, How we write)

The Patient Information Forum gives the same target: “PIF guidance is to aim for a reading age of 9-11 in health information.” (PIF reading age position statement)

Australia: the Style Manual

The Australian Government's Style Manual says: “Writing to an Australian year 7 level makes content usable for most people.” (Style Manual, Literacy and access)

Worldwide: the web accessibility guidelines

The Web Content Accessibility Guidelines (WCAG) set a reading level at their strictest level, AAA. Success criterion 3.1.5 covers writing that needs more than lower secondary education. It asks for a simpler version or extra help, such as a summary. WCAG counts lower secondary education as 7 to 9 years of school, so writing at grade 9 or below meets it. (W3C, Understanding Reading Level)

How this checker works

It splits your writing into sentences and words, counts syllables by their vowel sounds, and applies the published formulas. For a passage of nine words or more, the reading age is the Flesch-Kincaid grade plus five. For very short passages it leans on syllables instead, because the grade formula swings wildly on a handful of words. It's the same measure Copytone's studio uses.

Counting syllables by vowel sounds is quick but not perfect. It reads “prior” as one syllable and “diagnostics” as three. Treat the age as a rough guide, not a precise figure. SMOG was designed for 30 sentences or more, so on a short passage it's rough.

How to make writing easier to read

• Keep sentences short. One idea in each, and split any over 20 words.
• Use the everyday word: “use”, not “utilise”; “before”, not “prior to”.
• Put the plain term first and the medical term after it, as the NHS does: piles (haemorrhoids).
• Say who does what: “a doctor calls you”, not “you'll be contacted”.
• Read it aloud. If you run out of breath, the sentence is too long.

What a reading level can't tell you

A formula counts lengths. It can't tell whether a sentence is true, kind, in the right order, or in words your customers would use. As the Patient Information Forum puts it, readability tools “cannot tell you if text is appropriate, usable or logical.” Test your writing with real readers too.

It isn't a compliance check. An easy reading level doesn't make a claim allowed under advertising rules.

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