The chest size of an 8 year old is around 26 inches although it can vary slightly depending on the 8 year olds growth and development.
An 8 year old has an average chest size that ranges from 25.5 inches to 27 inches or 64 centimeters to 68 centimeters.
The average height of an 8 year old is around 48 inches to 50 inches.
And the average waist size of an 8 year old is around 23 inches to 24 inches or 58 centimeters to 61 centimeters.
The average weight for an 8 year old boy is around 57 lbs.
The average weight for an 8 year old girl is 53 lbs although this can also vary depending on the individual 8 year old child's build and genetics as some may weigh more than others and some may be taller than others.
As long as the child is not overweight or underweight it's perfectly okay for the child or 8 year old to be slightly different in weight which can be less weight or higher weight.
Some kids also eat more and put on more weight than others and some kids also get their weight from their parents through genetics or have conditions that make them weigh more.