Schools test reading level a few times a year and send home a letter or a number. Between those tests, parents mostly guess. The guess is usually fine, but it helps to know what you are guessing at, because a book that is a little too hard is useful and a book that is far too hard is a fight.
You do not need a test to get close. You need to listen to your child read a page out loud and pay attention to three things.
Three things to listen for
How many words they stop on. Ask your child to read a page and hold up a finger each time they hit a word they cannot get. The old rule of thumb is that five fingers on one page means the book is too hard for reading alone. One or two is about right. Zero on every page means it is time to go up a level, at least for practice reading.
Whether they are reading or decoding. A child who is sounding out most words is working on decoding, and the story is going by too fast for them to follow. A child who reads most words on sight and slows down only for new ones is following the story. Both are fine, but they want different books. The decoder needs short sentences with words they mostly already know. The reader can handle a plot.
Whether they can tell you what happened. After a page, ask what happened. Not a quiz, just “so what did she do?” If they can tell you, they were reading. If they read every word correctly and cannot tell you, the words were taking all their attention and the level is too high for reading alone. Read it to them instead and save it for later.
Do this over a few evenings rather than once. Tired children read a level below where they are.
What each band looks like on the page
There is no single scale that every school uses, but the bands below line up roughly with grades and with the way most leveled books are written. TaleBuilder writes to the same bands, so the kindergarten, grade 1 and grade 2 collections are a quick way to see what each looks like.
Kindergarten. Two to five words a sentence. One or two sentences a page. The picture shows exactly what the words say, and the same phrase often repeats from page to page. A child at this level reads “Wren looked fast. She scanned the rug.” with the picture doing half the work. Grandpa’s Wooden Train is a good example.
Grade 1. Four to seven words a sentence, two to four sentences a page. Simple dialogue. There is a real problem and a real solution, and the pictures support the text rather than carrying it. Emma’s First Day of School and Thunder Doesn’t Hurt are at this level.
Grade 2. Compound sentences. Three to five sentences a page. Characters have feelings that are shown rather than stated, and there are a few words the child will not have seen before. Mira and the First Rain and The New Kid’s Secret sit here.
Grade 3. Longer sentences with clauses, four to six a page, some figurative language, and sometimes a subplot. Chapter books start here for a lot of children.
Grades 4 and 5. Five to eight sentences a page, richer vocabulary, plot twists, characters with inner thoughts. Picture books at this level exist but most children have moved to chapter books.
A child’s grade and their reading band often do not match, in either direction. That is normal. Go by what you hear, not by the year they are in.
Picking a book once you know
For reading alone, pick the band where they stop on one or two words a page. That is where the practice happens.
For reading together, go one band up. They will follow the story because you are carrying the hard words, and they will pick up vocabulary they would not meet on their own.
For bedtime, go one band down. Nobody learns anything at 8pm, and an easy book that ends in a small success is a better way to close the day than a hard one that ends in frustration.
If the level is right and they still will not read
Then it is probably the subject, not the level. A child who will not touch a leveled reader about a farm will sometimes read the same sentences about their own dog, or a dinosaur, or a robot that dances at the wrong moments. That is a large part of why TaleBuilder exists: you pick the band, your child picks the topic, and you get a ten-page illustrated book at that band about that topic. Try one with them and see if it changes anything.