They all grow at different rates, so I can't give you an honest answer. However, with proper feeding you can expect close to 1,000 grams at a year old for females and 500 and up for males. That may vary on a lot of factors. The size of the meals you're feeding, the type of prey you are feeding, the frequency of feedings and your balls individual genetics. I've got two females that we born in early June (so about 4 months old) and they are both well over 300 grams. I've got a male that was born around the same time and he is a finicky eater so he is only in the 150g range. First thing is first, and I've said it a thousand times, get your ball on rats! They can eat appropriately sized rats right out of the egg. Second, you can pick up a cheap food scale at Wal-Mart for under $20. They work great.