There is no set number of pages for a novella. It can be anywhere from a couple of pages to a hundred pages. However, a novella is considerably shorter in length than a novel.
The Game - novella - has 192 pages.
Flirt - novella - has 192 pages.
Phallos - novella - has 95 pages.
The Assignment - novella - has 129 pages.
Murphy - novella - has 136 pages.
Storm - novella - has 60 pages.
The Thief - novella - has 96 pages.
Fear - Zweig novella - has 75 pages.
Inside Job - novella - has 99 pages.
Portrait of Jennie - novella - has 212 pages.
Hell Island - novella - has 108 pages.
Black Water - novella - has 154 pages.