Their return to top-flight football was sealed after second-place Leeds, who are four points behind them, were thrashed 4-0 in west London on Friday night.
Enzo Maresca's Foxes achieved promotion at the first time of asking having been relegated from the Premier League last season following a third-from-bottom finish.
An impressive campaign sees them currently sitting top of the Championship table after so far accumulating 94 points from 44 games.
Leicester is home to Socceroo Harry Souttar but the big defender has struggled for game time under Maresca, a former Manchester City assistant to Pep Guardiola.
Their final two games begin with a trip to Preston on Monday, before they round off the season with a home finale against Blackburn on May 4.
Defeat means Leeds sit only one point above third-place Ipswich, but the Tractor Boys have three more matches to play compared to the Yorkshire club's one.
Goals from Ilias Chair, Lucas Andersen, Lyndon Dykes and Sam Field secured QPR's own status in the league.
The Hoops, second from bottom following six straight defeats when Marti Cifuentes took over from Gareth Ainsworth in October, are now safe with a game to spare.
Leeds will be consigned to the promotion playoffs if third-placed Ipswich Town beat either Hull on Saturday night or Coventry in their game in hand on Tuesday.
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