Poodles are classified by their height, NOT their weight.
Tiny toy. Teacup. Microteacup. Pocket poodle.
These are simply classifications that breeders, have come up with over time, to further classify toy poodles into a variety of size ranges.
The caveat is there is no consistency or standardization with these terms. Each breeder may have a different definition for each of these categories.
While some breeders may guarantee the size of their puppies, we do not. The reason behind this is normal genetic variation. A toy poodle can in fact produce a miniature poodle when bred to another toy poodle, and vice versa. Quite a bit hinges on the genetics that get passed on. And different puppies grow at different rates. While we use toy breed growth charts to help predict likely size, it is not an exact science. (I've had puppies in the same litter by a small miniature sire out of a large toy girl come out as a very small toy, large toy and small miniature. Same litter.)
Additionally, "size" is not necessarily the same thing as weight. You can have a chubby toy poodle that weighs 9 pounds (that should weigh 6 pounds) and that is up to how that particular dog is fed and exercised, which is out of our control. You can see how that could make guaranteeing a pet stays, say, under 5 lbs, very challenging.
Our goals are to produce happy, healthy puppies - we do not focus on trying to breed the tiniest toy poodles available. Often dogs that are significantly smaller than the breed standard are also much higher risk for a number of medical conditions/problems and that is not something we are interested in producing.
We are always happy to entertain questions, including about size and weight as it can be a confusing and frustrating topic. We don't want anyone to be afraid to ask questions as that is the only way we can learn together and find you the absolutely best puppy to love!