This readability checker is free and needs no signup. Paste your text or enter a URL above. You get a Flesch reading ease score from 0 to 100, the Flesch-Kincaid grade level, your average sentence length, an estimate of passive voice and a list of every sentence over 20 words, longest first. UK public sector guidance sets targets you can check against.
UK targets to check your text against
- Reading age: the Home Office recommends writing for a maximum reading age of 9, even for a specialist audience. Surrey County Council aims for the same and says it matches GOV.UK's content design standard.
- Sentence length: GOV.UK's style guide says to break up or condense any sentence longer than 25 words. The GOV.UK blog that set the limit says sentences of 11 words are easy to read and those of 21 words are fairly difficult.
- Long sentences: every sentence over 20 words shows up in the list, longest first. Those past 25 words are over the GOV.UK limit.
Start with the longest sentence on the list and work down. Splitting one long sentence usually lowers the average sentence length and raises the Flesch score at the same time.
From the Home Office design manual, Surrey County Council's writing guide and the GOV.UK blog, read in October 2026.
What the checker doesn't tell you
It doesn't give a reading age in years. The Flesch-Kincaid grade is a US school grade, so read it as a guide to difficulty and don't treat it as a UK reading age.
It doesn't check spelling or grammar either, and it won't flag US spellings in UK copy. The passive voice figure is an estimate, so read the flagged sentences before rewriting them.
This readability checker is free with no signup. SearchBlueprint, who make it, sell SEO planning for websites: which searches each page should answer.