Klopp's current terms will keep him at Anfield until 2022, and in June he dismissed talk of signing a new deal at this stage.
After receiving the coach of the season award from Sport Bild this week, he told GianlucaDiMarzio.com (h/t MailOnline's David Wood): "I hope to continue like this, but in two, three years I don't know what may happen. Maybe I'll retire. It doesn't necessarily mean it will happen, but if that were the case, you wouldn't be surprised."
The coach was also asked if he would remain in charge of the Reds past 2022, move to Bayern Munich, return to Borussia Dortmund or take charge of the German national team.
"In the order I would like to do it," he said. "First national team, then Bayern, then back to BVB and then Liverpool for life. I have no idea. I really do not know that."
Klopp will be 55 by the end of his contract with Liverpool, where he'll have been for seven years—the same length of time he was in charge of previous clubs Mainz and Dortmund.
The German won his first trophy with the Reds in June as they beat Tottenham Hotspur 2-0 in the UEFA Champions League final.
Goal's Jack Sear hailed Klopp and the Liverpool board's backing of him:
Klopp also guided Liverpool to 97 points in the Premier League, although they fell short of Manchester City by one point.
For his efforts, he is among the nominees for FIFA's The Best Men's Coach award, which football writer Roy Nemer would give to him:
Liverpool supporters will hope to see Klopp continue at the club beyond 2022, given the transformative impact he has had during his first four years at Anfield.
Managing an elite team can be stressful, though—Pep Guardiola took a 12-month sabbatical after four years with Barcelona—so it's possible he might want a break.
Equally, a new challenge like Bayern or the national team could be available, and the change of scenery might appeal after a lengthy period on Merseyside.
If Klopp does leave Liverpool in 2022, he'll likely do so having won even more silverware with the club given the current trajectory under him.