General feeding charts do not take into consideration your dog's activity level. This is an extremely important factor when considering how much you need to feed your dog. Luckily, we found a dog food calculator that also incorporates your dog's activity level into calculating the the correct feeding amount. It also shows you how long a 15 lbs. bag of dog food will last you. Here's where you can find the calculator: https://****.com/dog-food-calculator/