Raising a puppy can be a guessing game, especially if you don't know its exact breed (or breeds). A dog that fits comfortably on your lap one year may barely fit in your apartment the next. If you're celebrating National Puppy Day (March 23, 2021) with a new pet of your own, you can use a classic trick to imagine how big they'll be as an adult.

According to Vet Street, the size of a puppy's paws can sometimes hold clues to their weight later in life. Dogs that grow to be large tend to have disproportionately big paws when they're young. The opposite usually goes for puppies with relatively smaller feet.

The trick is less of a foolproof approach than a fun rule of thumb (or whatever the dog equivalent of a thumb is). The physical features of dogs vary so much from breed to breed that big feet don't always translate to big bodies, and vice versa. Collies, for example, have relatively petite paws for their size, while bulldogs have chunky feet despite their small stature.

If you know your puppy's breed or anything about its genetic background, it will be easier to predict its size and appearance later in life. The less you know about your dog's parentage, however, the harder it will be to anticipate its development. Even vets are guessing when they tell you what a mixed breed puppy's size will be, and sometimes they get it wrong. So while it doesn't hurt to check your puppy's paw size for fun, maybe wait before upgrading the size of their bed to match their feet.