With about 2.3 children per household worldwide, he has to visit roughly 300 million households.
Spreading those households evenly across 69 million square kilometres of habitable land area on Earth (taking oceans, deserts, Antarctica and mountains into account), Father Christmas has to travel 144 million kilometres on Christmas Eve. That’s nearly the same as the distance from Earth to the Sun.
There was a great documentary made about this very thing this year. It was called Red One.
Check it out and have your mind blown!