The manga "Witch Hat Atelier" is approximately one-third complete. Its author, Kamome Shirahama, told Anime Corner that she has finished introducing readers to the magical world's workings and brought the story to a significant turning point:
"I would say we are about one-third of the way through the story, although it's very difficult to determine. The 'Silver Evening' arc was definitely a major turning point. The general outline of the plot and its ending are already planned, but the small details emerge directly during the work process."
At the time of the interview, 98 full chapters of the manga had been released, collected into 16 volumes. The first season of the anime concluded with chapter 23, at the end of the fourth volume. If subsequent parts maintain the same pace, the already published material will be enough for approximately four seasons, including the one that has aired.
If 98 chapters constitute approximately one-third of the story, the full volume of the manga could approach 300 chapters. At the pace of the first season, adapting the entire story would require about 12-13 seasons, or around 150 episodes. Of course, this is only an approximate calculation: future arcs may be longer, and the anime creators may accelerate or slow down the narrative.
The second season of "Witch Hat Atelier" has already been announced, but the premiere date has not yet been revealed.