It's very possible it doesn't. I've never tried it with smaller dogs.I don’t think that formula works for smaller dogs. That would make Nova bigger than her mom ..
It's also very possible it was just a fluke that it was accurate for Peggy. There are so many variables when it comes to growth. Peggy, for example, was underweight when we brought her home, and that threw the calculator WAY off for the first few weeks. It estimated she'd finish in the 30s. (I wish!)
Edit: Actually I did try it with a mini recently. Someone here was asking if their mini was likely to be bigger than the breeder said it would be. The calculator arrived at the breeder's exact estimate. Maybe the breeder used the calculator, too?? 😂