Puppy Weight Predictor

Expect an accuracy of roughly plus or minus 15-25% for individual puppies. The estimate improves with more data points (weighing the same pup at multiple ages), knowing both parent weights, and selecting the correct size class. Giant breeds are the hardest to predict early because their growth curve is long and individually variable.

Each method has a different systematic bias. The percentage method depends on the accuracy of the size-class table, which averages across many breeds. The growth-rate method is sensitive to whether the puppy's current weight is at a fast or slow phase of growth. Averaging the two reduces the error from either single method alone.

For mixed breeds, the best strategy is to enter the parent weights (in pounds) if you know them - the calculator will use the average as the adult target. If you have no parent information, select the size class that matches the larger parent's likely adult size.

Knowing the projected adult size helps you buy the right crate, harness, and collar before outgrowing them; select the correct large-breed or small-breed puppy food formula; and anticipate space and exercise needs. For large and giant breeds specifically, orthopedic health depends on choosing puppy foods that support controlled growth rather than rapid size gains.