The amount of food eaten by dog can tremendously vary from dog to dog. Generally, a dog should eat around 2% to 3% of its body weight per day. Therefore, if your dog weighs 10kg, it should be eating approximately 200g of food per day.
The amount of food dogs need to eat depends on their size, energy level, daily activities and health. There is no set formula for determining how much food to feed a dog, check with your vet to determine what amount might work for your dog.
You should follow the recommendations given by the manufacturer of the food you give your dog. You may want to divide the amount into two feedings if your pet seems hungry later in the day. You can find more information here: www.puppycare.com