Game Rules Guide

The base time is 24 hours for a small celebration and 30 hours for a large one. It is divided by the world speed and multiplied by 10 over your Town Hall level plus 9, then rounded up to a whole second, so a higher Town Hall makes it shorter. At world speed 1 a small celebration takes 24 hours at Town Hall level 1, and a large one, which needs level 10, takes at most 56,843 seconds (about 15 hours 47 minutes). Only the Town Hall level when you start the celebration counts, so upgrading it later does not shorten a celebration already running.