How many carbs should a 3-5 year old child eat every day?

Varies. Unless you are dealing with a very obese child or a child that is failing to thrive, you are not generally going to count carbs in this age group. Rather, concentrate on providing a good, well balanced diet with some fruits, lots of vegetables, whole grains and lean meats. If you are doing this, and your child is a healthy weight and growing appropriately, then the carb count is good.