As listed on the side of a box, there are 110 calories in a one cup serving of Cheerios. You must take into account your own serving size in order to find out the proper amount of calories, and also which type of Cheerios.
In the Cheerios cereal there are 110 calories, just the cereal, with 120ml milk it gets up to 180 calories and depends on what milk you are using. The milk with more fat rices up the calories.