Different buns come in different sizes. My mini rex is about 4lbs and i believe a normal rex weighs about 8lbs. My netherland dwarf is about 2.5lbs. We almost bought at 5month old mini lop who weighed about 3lbs. My neighbor had a flemish that weighed close to 20lbs

Have you tried googling “Rabbit Breed Chart” on google images? If thats your baby bun in your picture, it looks like an English Spot, but im not an expert so its mostly a guess

A true dwarf rabbit would have the dwarfism gene. Certain breeds have the dwarfism gene and it is part of the “breed standard” to get the desired look for that breed. Different dwarf breeds are different sizes. Maximum (allowable for showing purposes) size for Holland lops, for example, is 4lbs. A Nethie, on the other hand, has a maximum size of 2.5lbs. In all dwarf breeds, there are individuals that are larger and do not meet breed standards. This is typically because those individuals are false dwarfs (meaning they do not have a copy of the dwarfism gene).

Now there are smaller breeds that do not have a dwarfism gene as part of their genetic makeup. Many Dutch rabbits, for example, are only 4 or 5lbs. I wouldn’t call them a large rabbit.

As far as “normal” goes, I don’t think there is any way to define that. Wild European rabbits (from which domestic rabbits descended from) range in size from 2 to 6lbs. I suppose though that when people think of “normal” sized rabbits, they think of rabbits in the 5 to 8lbs range. But that is just my guess.