It depends on your target age group and on the book's reading level. Easy readers come in several difficulty levels, as I mentioned near the end of this post. In addition to the levels mentioned there, easy readers written for kindergarteners may use even fewer words in order to make the book as easy to read as possible -- what is sometimes called a Level 0 reader.
And while you may not have considered it, there's a difference between book manuscripts and magazine manuscripts. Clearly most children's magazine articles and stories aren't going to be as long as a book for the same age group.
So just how do you determine how long your manuscript should be? Here are a few guidelines from some best-selling books on the topic.
Debbie Dadey and Marcia Jones, author of the Bailey School Kids series, wrote a book called Story Sparkers: A Creativity Guide for Children's Writers. They said (on page 8) that most publishers look for easy reader/beginning chapter book manuscripts between 15 and 25 double-spaced pages in length. That sounds a bit long to me. If you assume 250 words to a double-spaced page -- a reasonable expectation -- that's 3750 words for a 15-page manuscript, 6250 words for a 25-page manuscript. That's way too long for an easy reader! (Those are perfectly good numbers for early chapter books, however.)
Tracey Dils, in her book You Can Write Children's Books, says (on page 33) that easy readers typically run 1000 to 1500 words.
Alijandra Mogilner's Children's Writer's Word Book echoes the same figures as Dils (on page 61) but adds that the low end is 500 words and the top end is 2000 words. She also says that magazines typically use pieces between 300 and 500 words, and as low as 100 words for the youngest kids (that last number is from page 53).
My own books run between 2000 and 2500 because I'm trying to write transitional books between easy readers and chapter books. (Note that I'm still well under the Dadey & Jones recommendations.) My chapters run between 300 and 400 words, about the same length as magazine articles for young children. That way, I figure they can read a chapter in one sitting.
And don't forget that I have a children's librarian double-checking my books. She's ok with the length, given that I'm trying to create a transitional book.
So I'd say these are safe guidelines for a typical easy reader:
- Easy readers range from 500 to 2000 words long, with 1000 to 1500 being the normal length. It's probably safe to say that a 500-word book will be for the youngest readers or for readers who are lagging a bit in their reading skills. (And yes, those kind of books are important if we want all our kids to become better readers. If you think you're good at writing them, you should definitely give it a try.)
- If you prefer to think in pages, the typical manuscript will be 2 to 8 full double-spaced pages long. The normal length would be 4 to 6 pages long. (1000 words = 4 pages of 250 words; 1500 words = 6 pages of 250 words.)