How many kilometres long is the Tour de France?

How to get close to this number

Build it from stages. The race runs about three weeks with roughly twenty-one racing days, and a road stage covers a distance a professional can ride in four to six hours — somewhere between 150 and 200 kilometres. Multiply stages by stage length and you land within a few hundred kilometres of the answer.

The comparison in the explanation is the one that makes it concrete: roughly the distance from Madrid to Moscow, covered on a bicycle in three weeks. Converting a sporting distance into a journey across a map is far more effective than the raw number, because a continental crossing is something people can picture and a four-digit kilometre figure is not.

The weight detail is the part that reveals the physiology. Riders lose several kilos across the race despite eating constantly, because sustaining that output for three weeks exceeds what the digestive system can supply — the same constraint as the calorie question on this site. The distance is the headline; the energy deficit is what actually decides who finishes.