"I still have five or six stories in mind. If all goes as planned, there should be at least 3 or 4 stories after the ant arc. Course of time, unexpected events occur and mess up your plans."
http://comicbook.com/anime/2018/02/24/hunter-x-hunter-anime-manga-how-long/
That is, if he doesn't die before then. Which I feel could happen at the rate his work has been coming along...