A year or two ago on these forums, people were speaking of the Naruto anime being contracted to have around 230 episodes. I'm assuming that 1) they are correct, and 2) the anime will complete the story in the manga. There should be about 150 anime episodes out, and they haven't even touched the Kakashi Gaiden yet. Making a rough, guestimate of rectal origins here, I'd say it would take about 14-18 episodes to cover up until the present in the manga, ignoring filler. Thats what makes me think the manga doesn't have too many chapters left.