The maths behind the sleigh
This calculator takes a rough count of children, spreads the deliveries across a night stretched by the world’s time zones, and works out the two numbers people love to argue about: how many houses per second Santa clears, and how fast the sleigh would have to fly to manage it. Slide the gifts per child and both figures climb.
It is a back-of-the-envelope model with clearly stated assumptions — a physics thought experiment for fun, not a claim about the real world. For the full story behind the numbers, read our Santa logistics article.
Frequently asked questions
How many houses does Santa visit in one night?
If about 500 million children in Christmas-celebrating homes get a visit and time zones stretch the working night to roughly 31 hours, that lands on the order of a few thousand homes every second.
How fast would Santa's sleigh have to travel?
To reach every household in the hours available, the sleigh would need to move at millions of kilometres per hour — thousands of times the speed of sound. It is a thought experiment, not physics that could really happen.
What assumptions does this calculator use?
A fixed number of children, one stop per household on average, and a night stretched by flying along with the time zones. Change the gifts per child and every total scales up.