Ian Rapoport of NFL Network reported the news Thursday. Butker can make up to $21.5 million with incentives.
The 23-year-old signed with the Chiefs in 2017 off the Carolina Panthers' practice squad. He's made 62 of 69 field goals and 93 of 97 extra points with Kansas City.
There is no word on how much of the contract is guaranteed.
The Chiefs had the NFL's highest-scoring offense in 2018 and are expected to rank among the league's best this season as well. Butker led the NFL with 65 extra points made but saw his field goals attempted drop from 42 to 27.
The new deal will give Butker the sixth-highest annual value for a kicker contract once the extension kicks in. The total value of Butker's contract ranks first among kickers when the 2019 season is included.
Justin Tucker of the Baltimore Ravens has the highest annual salary at the position at $5 million.