If you’ve just brought home a Brussels Griffon puppy, the calculator below estimates its adult size from its current weight — personalized to your dog, not just a breed average.
Estimates combine your puppy’s current trajectory with typical growth curves for this breed and size class. Individual dogs vary — nutrition, genetics and neuter timing all matter. For health concerns, ask your vet.
The Brussels Griffon is a toy-sized breed. Adult males typically weigh 8–10 lb (3.6–4.5 kg) and females 7–10 lb (3.2–4.5 kg). Most Brussels Griffons reach about half their adult weight around 3.2 months, hit 90% by roughly 6.7 months, and are fully grown near 9 months. Toy breeds finish growing fastest of all dogs — most of their gain happens before six months.
When do Brussels Griffons stop growing?
Most Brussels Griffons reach their full adult height and weight by about 9 months. Growth is fastest before 3.2 months, then slows steadily — by 6.7 months your puppy will be about 90% of its final size.
How much should a Brussels Griffon puppy weigh at 4 months?
A typical 4-month-old Brussels Griffon weighs roughly 5–6 lb, about 64% of its adult weight. Use the calculator above with your puppy’s exact weight for a personalized estimate — individual dogs vary.