The Royal Palace, Drottningholm Palace, The Chinese Pavilion, Gripsholm Castle:

The ticket is valid for entrance within an hour from the selected time on your ticket.  You can stay for as long as you like, but until closing time as the latest.

Please note that the following royal attractions are closed in 2020 and therefore are not included in this answer: The Royal Stables, Ulriksdal Palace, Rosersberg Palace, Strömsholm Palace, Tullgarn Palace, Gustav III's Pavilion, Rosendal Palace and The Riddarholmen Church.