Readability Test
Paste a paragraph and watch the score update as you type: Flesch reading ease, Flesch-Kincaid grade level, and the sentence and syllable averages driving both.
Start typing above to see your Flesch Reading Ease, grade level, and recommendations.
About this tool
Both scores come from the same two measurements: your average sentence length and your average syllables per word. The tool splits sentences on full stops, question marks and exclamation marks, and estimates syllables by counting vowel groups and discounting a silent trailing e. That heuristic is stable and instant, but it will misjudge names, acronyms and unusual spellings.
Underneath the two headline numbers you get raw counts and up to three recommendations, triggered when sentences run past 20 words, when word complexity climbs above 1.7 syllables, or when reading ease drops under 60. Nothing is sent anywhere, so unpublished copy stays on your machine.
Everything runs in your browser — nothing you enter here is sent to a server or stored. Provided as is, without warranty.
Reading scores are a smoke alarm, not a style guide
Flesch reading ease runs from 0 to 100 and rewards short sentences made of short words. Flesch-Kincaid takes the same two inputs and expresses them as a US school grade. Because they share their maths, they will never disagree with each other, and because they only count length, they cannot tell whether the words were the right ones. A paragraph of confident nonsense scores beautifully. This is worth internalising before you start optimising for the number.
What the score does catch, reliably, is the specific way founders write when they are close to their own product. Sentences grow subordinate clauses. Nouns get stacked into phrases like “customer onboarding workflow orchestration”. Latinate verbs creep in where plain ones would do: utilise for use, facilitate for help, leverage for anything at all. All three habits push the syllable average up, and the tool notices before your readers politely close the tab. For a landing page or a changelog, ease above 60 and a grade around 8 is a sensible target.
The caveat: this formula was built for continuous prose, and most web copy is not that. Bulleted lists, headings, code snippets and pricing tables all confuse the sentence splitter, because it counts a full stop as a boundary and nothing else. Paste a page full of bullets and the whole thing may read as one enormous sentence, tanking your score for no real reason. Test one prose section at a time. Conversely, a document written entirely in three-word fragments will score as very easy while being genuinely hard to follow, because rhythm and connective tissue are invisible to the maths.
Use it as a diff tool rather than a grade. Score a paragraph, rewrite the two longest sentences, score it again, and see whether the change actually helped. That loop is where the value is. If you are working through a page end to end, the meta description generator handles the snippet that gets people there in the first place, and our blog goes further into writing for people who are not developers.
Ready to see where agents can take cost out of your business?
Tell us about the process you want to optimise. Vlad personally reviews every brief and replies within one business day.