Amsterdam is entirely flat and compact, with the concentric canal rings forming a logical, almost elegant structure that makes navigation simple once you understand the layout. Most major sights sit within a walkable core, and canal bridges provide constant, photogenic waypoints along the way.
The real challenge for walkers is not distance or terrain but sharing the streets with cyclists, who move quickly and expect pedestrians to stay off marked bike lanes. Learning to spot the reddish bike lane paint and keeping to marked footpaths makes a big difference to a comfortable walk.
Streets narrow considerably in the oldest parts of the city, and cobblestones near the canals can be uneven, so a slower pace suits the atmosphere anyway. Distances between the centre and neighbourhoods like De Pijp or Jordaan are short enough to cover on foot without much effort.