The American team said before Hungary that the Danish driver will remain alongside Frenchman Romain Grosjean next year.
“I knew when I signed the contract that it was two years, so it’s not news for me,” Magnussen said.
“But I think it’s important for the team and for myself, because hopefully we will have no more of these kinds of questions,” he added.
Magnussen, 24, said certainty about his future is a new situation for him, having been at the centre of speculation when driving for his previous teams McLaren and Renault.
“It’s a nice situation, because for the two seasons I’ve done in formula one it’s been frustrating to talk about contracts every race,” he said.
Haas had a bad race weekend in Hungary prior to the August break, but boss Gunther Steiner said he is not worried.
“I wouldn’t jump to conclusions,” he told Ekstra Bladet newspaper.
“The midfield is so close that it can go either way every weekend. In Austria we were really good so it goes up and down,” Steiner added.