A 1-year-old Shih Tzu is about 15 in human years, a 5-year-old about 36, and a 10-year-old about 56. Shih Tzus usually live 10–18 years (about 56–88 human years).
How old is my Shih Tzu in human years?
Its name means "little lion" in Chinese, and it was bred as a palace companion. Like all dogs, Shih Tzus grow up fast: a 1-year-old Shih Tzu is about 15 in human years and a 2-year-old about 24. After that, the Shih Tzu follows the small-dog aging curve used by the AKC and AVMA, adding about 4 human years per year.
That means a 5-year-old Shih Tzu is about 36, a 10-year-old is about 56, and a 18-year-old is about 88 in human years. The old "multiply by 7" rule gets this wrong at almost every age — it says a 1-year-old Shih Tzu is only 7, when it's really a teenager.
Shih Tzu age chart: Shih Tzu years to human years
| Shih Tzu age | Human years | Life stage |
|---|---|---|
| 3 months | 4.5 | Puppy |
| 6 months | 10 | Puppy |
| 9 months | 12.8 | Young adult |
| 1 year | 15 | Young adult |
| 2 years | 24 | Young adult |
| 3 years | 28 | Young adult |
| 4 years | 32 | Mature adult |
| 5 years | 36 | Mature adult |
| 6 years | 40 | Mature adult |
| 7 years | 44 | Mature adult |
| 8 years | 48 | Mature adult |
| 9 years | 52 | Mature adult |
| 10 years | 56 | Mature adult |
| 11 years | 60 | Senior |
| 12 years | 64 | Senior |
| 13 years | 68 | Senior |
| 14 years | 72 | Senior |
| 15 years | 76 | Senior |
| 16 years | 80 | Senior |
| 17 years | 84 | Senior |
| 18 years | 88 | Senior |
| 19 years | 92 | Senior (beyond typical) |
| 20 years | 96 | Senior (beyond typical) |
Shih Tzu lifespan: how long do Shih Tzus live?
The typical Shih Tzu life expectancy is 10–18 years. In human terms, reaching 10 years is like reaching about 56, and 18 years is like reaching about 88 — so a long-lived Shih Tzu can be the equivalent of a person in their 80s.
Health concerns commonly discussed for Shih Tzus include brachycephalic (short-nose) breathing issues, eye problems and dental disease. Regular vet checkups, a healthy weight, daily exercise and dental care are the most reliable ways to help your dog reach the top of that range.
When is a Shih Tzu a senior?
The 2019 AAHA Canine Life Stage Guidelines define the senior stage as the last 25% of a dog's expected lifespan. For a Shih Tzu expected to live around 14 years, that begins at about 10.5 years (roughly 58 in human years). Watch for:
- A greying muzzle and cloudy eyes
- Sleeping more and slower walks
- Stiffness after rest, trouble with stairs or jumping
- Dental disease, weight changes or new lumps
Once your Shih Tzu is a senior, many vets recommend checkups about every six months.
How this Shih Tzu age calculator works
We map the Shih Tzu to the small size group (9–16 lb) and use the AKC/AVMA size-based chart: 15 human years at age 1, 24 at age 2, then the small-dog rate. Puppies under 1 year use veterinary life-stage milestones (about 10 human years at 6 months). The life stage follows AAHA guidelines, and we show the 2020 DNA-methylation formula (16 × ln(age) + 31) for comparison. For comparison, a large dog of the same age would be a different "human" age — see the dog age calculator by breed.
Frequently asked questions
How old is a 1 year old Shih Tzu in human years?
A 1-year-old Shih Tzu is about 15 human years old.
How old is a 5 year old Shih Tzu in human years?
A 5-year-old Shih Tzu is about 36 human years old.
How old is a 10 year old Shih Tzu in human years?
A 10-year-old Shih Tzu is about 56 human years old.
What is the Shih Tzu lifespan in human years?
Shih Tzus typically live 10–18 years, which equals about 56–88 in human years.
When is a Shih Tzu considered a senior?
Around 10.5 years old — the start of the last 25% of its average 14-year lifespan, following AAHA guidelines.
Is 1 dog year equal to 7 human years for a Shih Tzu?
No. A 1-year-old Shih Tzu is about 15 in human years, not 7. The aging rate then slows to about 4 human years per year for a small dog.
This calculator gives an estimate for education and fun. Every pet ages differently — for health decisions, talk to your veterinarian.