In order to maintain your canine companion’s health, it is important to understand where s/he is in the “life-stage” cycle. Both age and weight provide necessary information to classify your dog as adult, senior or geriatric. Depending on your dog’s life-stage classification, s/he may have different health needs. The numbers in the boxes on the accompanying chart represent an estimate of how old your dog is in human years, based on actual age and weight, assuming s/he is fit at the weights listed.