Welcome to you and adorable Fonzi!
The FCI breed standard for poodles reads:
Toy Poodles: Over 24 cm (with a tolerance of -1cm) up to 28 cm (sought after ideal: 25 cm).
FCI Standard No
Weight isn't part of the standard but naturally, a healthy weight for the height and structure is important. Puppies grow in spurts and sometimes even have a late spurt, seemingly after they've finished growing.
As twyla wrote, his mature adult size will depend on genetic inheritance from his parents, from what they inherited and on back thru generations.
"Small" is no less mighty!
