There is no best age to determine the bone age of a child, but it can be done between the ages of 3 and 15 years old, provided that the child is examined in a regular hospital and the symptoms that make it necessary to detect the bone age, such as delayed growth, significantly lower height than the same age, premature growth, significantly higher height than the same age and related symptoms of precocious puberty. If there are no indications for bone age testing, you should not give your child this test because it requires radiological examination and may have some effects on children.