This is a question that is impossible to answer. Each publisher uses different font sizes and page sizes so the amount of pages changes depending on the publisher.
358 pages
Most sources are in consensus that a movie version of Harry Potter and the Curse Child will not be made into a movie, due to the story being made specifically for the stage (and many people complaining about the problematic storyline). However, it is being premiered (as a play) in Broadway, spring of 2018.
Dwellers in the Crucible has 308 pages.
The Crucible of Time has 288 pages.
That Cursed House in Amityville has 230 pages.
Cursed Earth Asylum has 272 pages.
The book Moloka'i by Alan Brennert has 405 pages in its paperback edition.
With Child has 275 pages.
The Bad Book by Andy Griffiths has approximately 200 pages.
The Atonement Child has 375 pages.
Fiela's Child has 314 pages.
Bog Child has 337 pages.
Child of Fortune has 467 pages.
Child of the Hunt has 324 pages.
A Word Child has 392 pages.
A Child Called 'It' has 206 pages.