The Harry Potter series has a reading level of 870L, which means that an average 8th grader should be able to read these books with moderate ease. However, the reading level varies from book to book, and it also depends on the particular child. Here are some general guidelines for the appropriate age and grade at which each book in the series should be read:

• Harry Potter and the Sorcerers Stone: 8+ / 2nd and 3rd grade
• Harry Potter and the Chamber of Secrets: 8+ / 2nd and 3rd grade
• Harry Potter and the Prisoner of Azkaban: 9+ / 3rd and 4th grade
• Harry Potter and the Goblet of Fire: 10+ / 4th and 5th grade
• Harry Potter and the Order of Phoenix: 12+ / 5th and 6th grade
• Harry Potter and the Half-Blood Prince: 12+ / 6th and 7th grade
• Harry Potter and the Deathly Hallows: 12+ / 6th and 7th grade

The first book in the series, Harry Potter and the Sorcerer's Stone, requires a reading level of 880L, which makes it an appropriate read for most 2nd and 3rd graders. The reading level requirement increases as the series progresses, with the most complex book of the series, Harry Potter and the Half-Blood Prince, having a reading level requirement of 1050L, making it recommended for any 6th-8th graders who reach this level.