The Tosa Inu, also known as the Tosa Ken, is a large and powerful dog breed originating from Japan. This breed exhibits significant variation in size, primarily due to breeding standards in different regions. Typically, the Tosa Inu stands about 24.5 to 32 inches at the shoulder and can weigh anywhere from 100 to 200 pounds. Males generally are larger and heavier than females. Known for their muscular build and imposing presence, these dogs combine strength and agility, making them highly effective as guard dogs or in competitive dog sports such as weight pulling and obedience trials. Their robust physique mirrors their dignified and calm demeanor.

Male Tosa Inu Weights & Heights by Age

The following chart contains the average weights and heights of male Tosa Inu from newborn to 3 years of age. Please note these are only averages. Always consult with your veterinarian if you have any concerns about your Tosa Inu’s growth.

Age (Months)
Weight (lbs)
Weight (kg)
Height (inches)
Height (cm)

0
7.5
3.4
7
18

1
14
6.4
9
23

2
25
11.3
12
30

3
40
18.1
15
38

4
55
25
18
46

5
70
31.8
21
53

6
85
38.6
23
58

7
100
45.4
25
64

8
115
52.2
26
66

9
130
59
27
69

10
145
65.8
28
71

11
155
70.3
29
74

12
170
77.1
30
76

24
200
90.7
32
81

36
200
90.7
32
81

Female Tosa Inu Weights & Heights by Age

The following chart contains the average weights and heights of female Tosa Inu from newborn to 3 years of age. Please note these are only averages. Always consult with your veterinarian if you have any concerns about your Tosa Inu’s growth.

Age (Months)
Weight (lbs)
Weight (kg)
Height (inches)
Height (cm)

0
6.5
2.9
6
15

1
12
5.4
8
20

2
20
9.1
10
25

3
33
15
13
33

4
45
20.4
16
41

5
60
27.2
19
48

6
75
34
21
53

7
85
38.6
23
58

8
95
43.1
24
61

9
105
47.6
25
64

10
115
52.2
26
66

11
125
56.7
27
69

12
135
61.2
28
71

24
165
74.8
30
76

36
165
74.8
30
76

These tables are based on general guidelines and can vary greatly depending on individual dogs. Always consult with a veterinarian or professional breeder for more specific information about your pet’s growth and development.

FAQs about a Tosa Inu Puppy’s Growth and Development

1. What is the average weight of a Tosa Inu puppy at 3 months?
At 3 months, a male Tosa Inu typically weighs about 40 pounds (18.1 kg), and a female averages around 33 pounds (15 kg). This rapid growth is characteristic of the breed, reflecting their large breed status. It’s important to monitor their weight to ensure they are not growing too quickly or slowly.

2. How quickly do Tosa Inu puppies grow?
Tosa Inu puppies grow very rapidly in the first year, especially during the first six months. Their growth rate might slow down after six months but continues steadily until they are about 12 months old. This rapid early growth requires careful nutritional management to avoid joint issues.

3. What is the expected height of a Tosa Inu at 6 months?
By 6 months, male Tosa Inu puppies are expected to reach around 23 inches (58 cm) in height, while females typically stand about 21 inches (53 cm). This growth in height accompanies significant weight gains during this period.

4. When do Tosa Inu puppies reach their full height?
Tosa Inus generally reach their full height by 12 months of age, but some may continue to fill out and add a bit of height until 18 months. Males usually reach about 30-32 inches (76-81 cm), and females slightly less at around 28-30 inches (71-76 cm).

5. What should I feed my Tosa Inu puppy to support healthy growth?
Feed your Tosa Inu puppy a high-quality diet formulated for large breed puppies. Such formulas help manage their rapid growth through balanced nutrition, avoiding excessive calories that can lead to rapid growth and potential joint issues. Proper calcium and phosphorus ratios are critical.

6. How can I tell if my Tosa Inu puppy is overweight?
Check if you can feel your puppy’s ribs without a thick layer of fat; ribs should not be visible but easily palpable. Look for a waist when viewing from above and a tucked abdomen when viewed from the side. Consult your vet if you’re concerned about your puppy’s weight.

7. What is the growth rate difference between male and female Tosa Inus?
Male Tosa Inus generally grow larger and heavier than their female counterparts. This difference starts to become noticeable from about 3-4 months of age, with males continuing to grow at a slightly faster and more prolonged rate.

8. How much exercise does a Tosa Inu puppy need?
Tosa Inu puppies should have moderate exercise to manage their energy levels and support healthy growth. Avoid strenuous activities that can strain their developing joints, like forced running or jumping, until they are fully grown.

9. Is there a growth spurt in Tosa Inu puppies?
Tosa Inus experience significant growth spurts, particularly between 2-6 months. These spurts can be sudden and dramatic, with noticeable changes in both weight and height over short periods.

10. How do I monitor the growth of my Tosa Inu puppy?
Regular vet check-ups are essential. You can also weigh and measure your puppy at home monthly to ensure they are on the right growth curve for their age and breed.

11. Can the growth of a Tosa Inu puppy indicate future health issues?
Yes, improper growth rates can lead to health issues like hip dysplasia or other joint problems, particularly in large breeds like the Tosa Inu. Consistent, not overly rapid growth is ideal for preventing such issues.

12. What are common signs that a Tosa Inu puppy is not growing properly?
Lethargy, reluctance to play, visible bone protrusions, and irregular eating habits can all be signs of growth problems. If you notice any of these signs, consult your veterinarian for advice.

13. Does neutering or spaying affect the growth of Tosa Inu puppies?
Neutering or spaying can affect the growth of Tosa Inu puppies, potentially leading to a taller stature as the closure of growth plates might be delayed. Discuss the best timing with your vet to optimize health and growth.

14. What health problems can affect Tosa Inu growth?
Tosa Inus can be prone to joint issues such as hip dysplasia, especially if they grow too quickly. Proper diet and controlled exercise are important to minimize the risk of these developmental problems.

15. At what age is a Tosa Inu considered fully grown?
While Tosa Inus generally reach their full height by 12 months, they may continue to fill out and gain muscle until about 2-3 years of age. They are considered fully matured at around 3 years old.

16. How often should a Tosa Inu puppy be fed?
Up to 6 months, it’s advisable to feed your Tosa Inu puppy three to four times a day. After six months, you can reduce feeding to twice daily. This helps manage growth and energy levels without overloading their digestive system.

17. Why is controlled growth important for Tosa Inu puppies?
Controlled growth helps prevent stress on the developing bones and joints, which is crucial for preventing future orthopedic issues, common in large breeds like the Tosa Inu. This involves managing diet and exercise.

18. How should I adjust food portions as my Tosa Inu puppy grows?
Food portions should be adjusted based on the puppy’s age, weight, and activity level. Regular weight checks will help you determine if their food intake needs to be adjusted to avoid underfeeding or overfeeding.

19. What role does genetics play in a Tosa Inu’s growth?
Genetics plays a significant role in determining the size a Tosa Inu will ultimately reach. The size of the puppy’s parents can give a good indication of its expected adult size, though individual variation does occur.

20. Can environmental factors affect my Tosa Inu’s growth?
Yes, factors such as diet quality, exercise amount, and overall care can greatly influence the growth and health of a Tosa Inu. A nurturing environment that provides proper nutrition, veterinary care, and appropriate exercise is essential for optimal growth.