Average weight of a 4 year old child in kg?

There is no ideal or perfect weight for a 4-year-old boy or girl (or a child of any age). Weight is related to height and body composition rather than age. Feel free to ask the question again and include more detail. Alternatively, for in-depth information about weight in relation to height, and to see the distribution of weights and heights of children at various ages, please see the page link, further down this page, listed under Related Questions.