All Things Anime & More
One Piece, is a Japanese manga series written and illustrated by Eiichiro Oda, The story line covers a young lad who strives to become the Pirate King “Kaizoku-ō” and become a free pirate who isn’t restricted by anything “Complete Freedom”.
Eiichiro Oda in an interview said:
How far along is the story right now, percentage-wise?A: He told me that the first part of the story, the part prior to the time-skip, was around halfway through. That was about 60 volumes, so maybe we’re at 70%? I don’t think it’s at 80% yet. Something like that
Lets calculate based on this, if we going to count it, One Piece manga serialized at July 19th, 1997 and statement for recent progress at July 17th, 2015(interview date) stand for approximate 70% progress, so far we got around 18 years of serialization.
100 percent / 70 percent * 18 years = 25.7 years ~25 years and 7 months (approx)
Assuming it needs to take around 26 years, maybe we get 2023 as the year of one piece to finish.
So One Piece will end in the year 2023.
This is not an exact number or a date when it will end but based on the information we have this becomes a fair estimate.