Most store-bought dog food bags have a feeding guide for distributing the daily amount of food. This guide is based on dog weight, but the recommended amount may vary based on the richness of the food. The actual amount consumed is directly related to the attitude of the dog, and their activity and metabolism rates, their gender and their ages.
For my dogs, they fall within the 15-25 pound range (the 13-year-old is 15 lbs, the 5-year-old is 23 lbs) and their individual foods both recommend 1 cup of kibble per day. I divide it into two 1/2 cup meals (morning and evening). The vet stated both dogs are at the correct weight for their individual sizes; they are not overweight.
The 23 lb dog sometimes doesn't eat all of her food in the morning, to which I add the other 1/2 cup in the evening. She sometimes doesn't eat all of it. She is not overweight and she doesn't eat other things. She is the more active of the two dogs. The 15 lb dog only picks in the morning and consumes everything at night, including some of the larger dog's kibble. He is somewhat inactive, but I believe he has a high metabolism.