I use a Chefmate scale that I bought at target. It weighs up to 11 lbs. the puppies fit perfectly, for my adults and older puppies I use a 5 gallon ice cream tub and place them in it. It weighs accurately. It is usually exact to the Vet's scale or just off by an ounce +/-. It is really easy to use and when using the tub it has a one touch zero out. I love it. here is the link to read about it.
Chefmate® Digital Stainless Steel Scale : Target