The younger the child the faster the broken bone will heal. The average time for a broken bone to heal in a child is 4-6 weeks. Adult broken bones typically take twice as long to heal than children.
Bone healing time is dependent on the type of fracture and which bone is involved. Typically the higher the energy that caused the fracture will result in a more complex fracture and a longer healing time. For example, if a child falls while running and lands on their out stretched wrist and fractures their distal radius, that fracture will heal quicker than a fracture that occurs in a high energy car accident.
Certain bones such as the tibia (shin bone) take almost twice as long to heal than the distal radius (wrist bone). Imaged below on the left is a higher energy wrist fracture that will take longer to heal than the image on the right. The X-ray on the right is a non displaced distal radius fracture indicated by the red arrows.