I like this calculator it used the calories in the dogs food since they all can vary alot. You can Use the bag amount it says to feed also for a gauge. But it usually is alot more. Puppies should get as much as they want. I don't free feed my adult dog. He will eat 10lbs if I let him. I keep him at an ideal weight for his health. He is more like a few oz over. But ime when you let your Small breed dogs get 1-2 lbs you can see it in there walk. Its labored. I can see it in Moki when he is 7# 5oz or 6# 12 oz. The way he runs and moves. He probably should weight 6# 6 oz. Just by feeling his body. But a little weight isn't bad but way over is. Big dogs are different. They can have extra in lbs. You can Google the calculator you want. They are all pretty close. This is just easy imo. But feeding more times is better. Then less for puppies. But if you search you can find feeding adult dogs less is better. I dunno I still feed 3x
Dog Food Calculator How to Estimate the Right Dog Food Serving Size for Your Pet