How many bicycles are there in Amsterdam?

How to get close to this number

The population is the answer, near enough. In a city where cycling is the default way to move, the ratio of bicycles to people approaches one, and many households own more than one bike while some residents own none — which cancels out close to parity. So the reliable route is to recall the city's population and adjust very slightly, rather than to estimate bicycles at all.

The instinct to guess far below the population comes from living somewhere cycling is a hobby. In most cities a bicycle is recreational equipment owned by a minority; here it is transport infrastructure owned by nearly everyone, including people who also own a car. Questions about a place famous for one thing usually hinge on realising that the thing is ordinary there rather than exceptional.

The canal figure in the explanation is the detail that makes the scale tangible: a municipal boat exists purely to dredge bicycles out of the water, and it recovers thousands every year. A city only funds a dedicated vehicle for a problem when the problem is routine, which tells you more about bicycle density than the headline count does.