The definition
A decodable book uses only the letter-sound patterns a child has already been taught, plus a small set of sight words they know. If your child has learned short vowels and simple consonants, a decodable book contains The cat sat on a mat — and not The beautiful horse galloped away.
How they differ from levelled readers
Levelled readers are graded by sentence length, vocabulary and picture support. They frequently contain patterns the child has never been taught — which leaves guessing as the only available strategy. They are often highly repetitive and heavily illustrated, so a child can appear to read them fluently while barely looking at the words.
Decodable books are graded by phonics knowledge instead. Every word is workable with what the child already has.
Why it matters
Success in a decodable book comes from decoding, so decoding is what gets reinforced. Success in a mismatched levelled reader comes from guessing, so guessing gets reinforced — and each successful guess makes the habit stronger and harder to break later.
When to move on
Decodable books are a scaffold, not a destination. Once a child decodes confidently and reads with reasonable fluency — usually after vowel teams and Magic E — move to real books. Staying too long is its own problem: decodables are constrained by design and rarely good stories.
Keep reading rich, difficult books aloud to your child throughout. What they can read themselves and what they can understand are very different things, and the gap is where vocabulary grows.
