Free tool
Paste a passage, pick the lesson your student is on, and see what Cody sees: every word coloured by whether the reader can sound it out, which ones they cannot yet, and why. It is the same scorer, the same lesson rules and the same dictionary Cody holds its own stories to. Switch to compare mode to put a Cody story next to one a chat assistant wrote for the same lesson.
Prefer a full page? Open the checker on its own.
Decodability is not a property of a text on its own. It depends on what the reader has been taught. Pick a lesson and the checker knows every letter-sound pattern introduced up to that point, plus the high-frequency words the program has taught by then.
Each word is looked up in a dictionary of more than 180,000 entries with its spelling patterns mapped. If every pattern in the word has been taught, the reader can sound it out. If even one has not, they would have to guess.
A name is told to the reader once, so it counts as read rather than as a failure. Digits and dates have no sounds to blend, so they are left out of the count altogether. Neither one can inflate or deflate a score.
Cody will not hand a teacher a story below 90% decodable for the chosen lesson. Research on decodable text typically cites a range between 80 and 90 percent; we hold to the top of it because a beginning reader who has to guess one word in five stops decoding and starts memorising.
Every word in your passage is marked as one of four kinds. Three of them count as read; the fourth is what pulls the score down.
Numbers are the one thing with no colour and no tag: digits and dates have no sounds to blend, so they are left out of the count rather than scored either way.
Ask a general assistant for a decodable story for a first grader and it writes something short and cheerful with simple sentences. Simple is not the same as decodable. It will happily reach for bright, sparkling, friends and beautiful, each of which uses a spelling pattern most first graders have not been taught yet. It has no idea which lesson your reader is on, so it cannot stay inside it. Paste one here and the red words show you exactly where it wandered off.
No. This page sends your text to the same analyzer that scores every story Cody generates, with the same lesson rules and the same dictionary. One honest caveat: when Cody writes a story it also knows the teacher's topic words and can use a language model to spot names, so a story's own page can credit a word or two that a pasted copy cannot. Put the names in the names box and the two agree.
Decodability is necessary, not sufficient. A passage can be 100 percent decodable and still be dull, incoherent or wrong for a child's interests. Cody's own stories go through separate checks for coherence and content; this tool measures one thing, on purpose, so the comparison is fair.
The dictionary is large but not infinite, and it deliberately leaves out most proper nouns. Put names in the names box so they are credited. If an ordinary word is missing, it counts against the passage until we add it, which is the conservative choice.