What is a decodable book?

September 2, 2026

Decodable books are controlled texts. Every word is built from spellings the child has already been taught, so the child can read the whole book independently by sounding out. Nothing in it needs guessing at.

That is the definition. Executing it is harder than it sounds, and plenty of books sold as phonics books do not manage it.

The thirty-second check

Open the book. Read one page. Ask the same question of every word: could my child work this out from the sounds they know?

All yes, and the book is decodable for your child. Three words with no route in, and the reading will end badly, because a child who meets a word they cannot decode will guess at it.

Note "for your child". Decodability is not a fixed property of a book. It depends entirely on where the reader has got to, so a book that fits perfectly in November may be far too easy by March.

Five things to look for before you buy

1. The new spellings taught in this book.

2. The previous spellings assumed from earlier books.

3. The tricky words, each one named. They go by several titles, including common exception words and helper words, and most are far more regular than the label suggests.

4. A sequence. A number on the book, placing it in an order.

5. A readable page. Every word reachable by sounding out.

All five, and you have a decodable book. No lists at all, and you are taking the cover's word for it.

Books are also meant to be read more than once, so buy fewer and reread them.

Sounds and spellings are not the same thing

English has around 44 sounds, depending on your accent, and far more than 44 ways of writing them. The sound /f/ can be written f, ff, ph or gh. The letters ea say three different things in bead, bread and break.

So when a book says it introduces s, a, t, i and m, those are spellings. Good series are organised by spellings, a few at a time, because the spellings are what a child has to learn to look at.

This is why book seven of our first set introduces ff, ll, ss and zz. Your child already knows /f/, /l/, /s/ and /z/. What is new is a second way of writing each one. Plant that idea early and the rest of English is far less baffling.

Why the order matters

Decodable books are cumulative. Each one adds a few new spellings and keeps everything before.

Here is Set 1 of Tip Top Phonics.

Book	New spellings	Its reading list
1. Mim	s, a, t, i, m	Mim, Sam, sit, mat, Tam
2. On Top	n, o, p	Pop, Pip, Nat, nap, tap, top, not, pat, tip
3. A Big Cat	b, c, g, h	big, bog, bop, can, cat, gap, got, him, hop, hot
4. A Den	d, e, f, v	den, dig, dips, dog, fan, fed, get, pet, Viv
5. Lug the Log	k, l, r, u	fun, kid, log, lug, must, run, tug, up
6. Sam is in a Jam	j, w, z	jam, jet, jog, wet, zag, zig, zip
7. Is it a…?	x, y, ff, ll, ss, zz	buzz, fell, fox, hiss, huff, puff, yak, yell
8. Viv	none, review	bed, hill, hug, ill, jogs, pups, yells

Five spellings and five words in book one. That is all the raw material needed for a whole book – and it is why a four-year-old can read it independently in their first week of phonics.

Notice how gradually the set grows. Book two introduces just three new spellings; book three adds four more. A child who already knows s, a, t, i and m can pick up book two and meet only n, o and p as new spellings.

Book eight introduces nothing new. The final book in a set is there to consolidate, giving children the chance to read with everything already familiar before they move on. If a set is still introducing new spellings in its final book, it has been sequenced badly.

Where books go wrong

Spellings the child hasn't met. Sock in front of a child who has not been taught ck is an invitation to guess. In our own series ck waits until book seven of Set 2.

Words carried by the picture. If the only route to elephant is the elephant, the book is not teaching reading.

Predictable, not decodable. Repeating sentence frames where only the last word changes can sound fluent while requiring very little decoding.

Labelled by age. "Ages 4 to 6" tells you nothing about what the child has been taught.

Does it matter if they are enjoying it?

Yes, and the two are not in competition.

A child decoding the book in front of them is doing something difficult and succeeding. That is where reading confidence comes from. A child working through a book they cannot read is learning that reading is guesswork, and that is harder to undo later than to avoid now.

The DfE Reading Framework is clear that children should read books matched to the phonics they have been taught.

The evidence behind phonics itself is strong. The Education Endowment Foundation draws on 228 studies and puts the average impact at five additional months' progress. It is equally clear that phonics improves the accuracy of a child's reading but not necessarily their comprehension, and that vocabulary and comprehension need teaching alongside it.

Both halves of that matter to us. Decodability is what makes a story readable at this stage. Everything else about the book still has to be good.