Shih Tzu Age Chart: Dog Years to Human Years

If you’re wondering how old your Shih Tzu is in human years, the short answer is this: a 1-year-old Shih Tzu is about 15 human years old, a 2-year-old is about 24, and after that each dog year adds roughly 4 human years. So a 10-year-old Shih Tzu is around 56, and a 16-year-old is around 80.

The Shih Tzu age chart below converts every age from 2 months to 20 years into human years, with the matching life stage for each one. If you prefer an instant result, you can enter your dog’s age in the Shih Tzu dog age calculator.

The old rule that one dog year equals seven human years doesn’t work for this breed. Shih Tzus grow fast in their first year, reach maturity early, and then age slowly the way small companion breeds do. A 1-year-old Shih Tzu is closer to a teenager than to a 7-year-old child.

Below you’ll find the full conversion chart, a separate puppy chart, what each life stage means, how long Shih Tzus typically live, and answers to the ages people ask about most.

Shih Tzu Age Chart: Dog Years to Human Years (2 Months to 20 Years)

The chart below shows the estimated conversion from Shih Tzu dog years to human years. This is the fastest way to check your dog’s approximate human age and life stage.

Because Shih Tzus are small dogs, they usually age more slowly than large dogs after the first few years. That is why a Shih Tzu age chart is more useful than a general dog age chart.

Shih Tzu Dog Age to Human Age Chart

Shih Tzu Age	Human Age Equivalent	Life Stage
1 year	15 years	Puppy / young adolescent
2 years	24 years	Young adult
3 years	28 years	Adult
4 years	32 years	Adult
5 years	36 years	Adult
6 years	40 years	Adult
7 years	44 years	Adult
8 years	48 years	Mature adult
9 years	52 years	Mature adult
10 years	56 years	Senior
11 years	60 years	Senior
12 years	64 years	Senior
13 years	68 years	Senior
14 years	72 years	Senior
15 years	76 years	Senior
16 years	80 years	Senior
17 years	84 years	Senior
18 years	88 years	Advanced senior
19 years	92 years	Advanced senior
20 years	96 years	Advanced senior

This chart gives an estimate, not an exact medical age. Your Shih Tzu’s real aging speed can depend on genetics, weight, activity level, diet, dental health, and overall care.

For a faster input-based conversion, you can also use the Shih Tzu dog age calculator and enter your dog’s exact age.

Shih Tzu Puppy Age Chart: 2 Months to 1 Year

Shih Tzu puppies age fastest in their first twelve months, so the early months cover a lot of human-equivalent ground very quickly.

Shih Tzu Puppy Age	Human Age Equivalent	Stage
2 months	About 3 years	Young puppy
3 months	About 5 years	Puppy
6 months	About 10 years	Older puppy
9 months	About 13 years	Adolescent
12 months	About 15 years	Young adolescent

Most Shih Tzus reach their full adult height and weight between 9 and 12 months, though some continue filling out through the chest until around 18 months. A one-year-old Shih Tzu is physically grown but usually still behaves like a teenager.

How to Read This Shih Tzu Age Chart

• The first year equals about 15 human years because Shih Tzus mature quickly.
• The second year brings your Shih Tzu to about 24 human years.
• After age 2, most Shih Tzus age by about 4 human years for each dog year.
• A Shih Tzu is usually considered a senior around age 10.

This means a 7-year-old Shih Tzu is about 44 human years old, a 12-year-old Shih Tzu is about 64, and a 15-year-old is roughly 76. Shih Tzus who live past that are uncommon but not rare – a 16-year-old is about 80 in human years, and an 18-year-old is around 88.

What “Shih Tzu Dog Years” Actually Means

People use the phrase “dog years” in two different ways, which is why the same question can have two answers.

• Dog years to human years. This is the usual meaning and the one the chart above uses. Your Shih Tzu’s actual age converts into a human-equivalent age – so 6 dog years is about 40 human years.
• Human years to dog years. Some people ask the reverse: what would a 6-year-old human be as a Shih Tzu? Working backwards from the same chart, that lands well under one year old – a Shih Tzu is still a puppy at that point.

If you are asking how old your Shih Tzu is in dog years, the answer is simply their real age in calendar years. The chart converts that into human years for you.

For a deeper breakdown of breed traits and care needs, see our complete Shih Tzu dog guide.

Why Shih Tzu Dog Years Are Not Equal to 7 Human Years

You may have heard that one dog year equals seven human years. This rule is common, but it is not accurate for Shih Tzus.

Dogs do not age in a straight line. They grow very fast at the start of life, then their aging slows down later. A Shih Tzu can reach adult size in about the first year, while humans take many years to reach the same stage of development.

The 7-year rule does not work well because:

• Shih Tzus mature quickly in the first year
• The second year still adds a large amount of human-equivalent age
• Adult aging slows down after age 2
• Small dogs like Shih Tzus often live longer than large dogs
• One fixed formula cannot match every breed and size

For example, a 1-year-old Shih Tzu is closer to a teenager than a 7-year-old child. A 10-year-old Shih Tzu is not exactly 70 in human years; using a small-breed chart, they are closer to about 56 human years.

How Long Do Shih Tzus Live? (In Dog Years and Human Years)

Most Shih Tzus live between 10 and 16 years, with around 13 years being typical. That is a long life for a dog – small and toy breeds generally outlive large breeds, and the Shih Tzu sits comfortably in the upper half of that range.

Put into human years using the chart above, a Shih Tzu who reaches the breed average of 13 years is roughly 68 in human years. One who reaches 16 is about 80.

Shih Tzu Lifespan Milestone	Age in Dog Years	Human Years Equivalent
Enters senior stage	10 years	56 years
Breed average lifespan	13 years	68 years
Upper end of typical range	16 years	80 years
Exceptionally long-lived	18-20 years	88-96 years

A few things influence where an individual dog lands in that range. Female Shih Tzus tend to live around a year longer than males on average. Weight matters too – dogs kept at a healthy weight generally do better in their later years than overweight ones. Genetics, dental health, and consistent veterinary care all play a part.

The oldest Shih Tzu on record is widely reported to have reached about 23 years, though that figure has never been formally verified. It is far outside the norm, but it shows how much room there is above the average.

Shih Tzu Life Stages Explained: Puppy, Adult, and Senior Years

Understanding your Shih Tzu’s life stage is just as important as knowing the number in human years. Life stage helps explain changes in behavior, energy, sleep, exercise needs, and health care.

Most Shih Tzus move through three main life stages: puppy, adult, and senior.

Shih Tzu life stages by age

Shih Tzu Age	Life Stage	What This Means
0-1 year	Puppy	Fast growth, training, social learning, high energy
1-9 years	Adult	Stable energy, full size, active daily routine
10+ years	Senior	Slower movement, more rest, possible age-related changes

Puppy stage: birth to 1 year (when a Shih Tzu is full grown)

Shih Tzu puppies grow quickly during the first year. This is the stage when they learn basic training, build social confidence, explore their environment, and develop daily routines.

Most Shih Tzus are full grown between 9 and 12 months, when they reach their adult height and weight. Some keep filling out through the chest until around 18 months, but the main growth is finished by the first birthday.

• They need gentle training and socialization
• They usually have short bursts of playful energy
• They need age-appropriate meals and vet visits
• They may reach adult size by around the end of the first year

Adult stage: 1 to 9 years

The adult stage is usually the longest part of a Shih Tzu’s life. During this stage, most Shih Tzus have more predictable behavior, steady energy, and a more settled daily routine.

• Energy levels are usually steady
• Behavior becomes calmer and more predictable
• Weight control becomes important
• Regular grooming, dental care, and checkups help support long-term health

For help with behavior routines during this stage, see the Shih Tzu training guide.

Senior stage: 10 years and older (when a Shih Tzu becomes a senior)

A Shih Tzu is usually considered a senior dog around age 10. This does not mean your dog is suddenly unhealthy, but it does mean their care needs may start to change.

• They may sleep more than before
• Walks may need to become shorter or slower
• Vision, hearing, teeth, joints, or memory may change with age
• Vet checkups may become more important for early problem detection

Senior Shih Tzus usually benefit from more frequent vet visits than adults, and dental checks matter especially, since small breeds are prone to dental problems as they age. Not all senior Shih Tzus age the same way – some 12-year-olds remain playful and alert, while others need extra comfort and support earlier.

Care Priorities at Each Shih Tzu Life Stage

Once you know your Shih Tzu’s age in human years, it is easier to see what kind of care they need. A puppy, an adult and a senior have very different energy levels, food needs and health risks – and the gap between a 2-year-old and a 12-year-old is roughly the gap between a 24-year-old and a 64-year-old person.

Life Stage	Main Care Focus	What to Watch For
Puppy	Growth, training, vaccines, socialization	Fast growth, chewing, house training, short attention span
Adult	Weight control, exercise, grooming, routine checkups	Weight gain, dental buildup, low activity, skin or coat issues
Senior	Comfort, joint support, dental care, regular vet checks	Slower movement, more sleep, vision, hearing, or behavior changes

Weight control is the one that matters most across every stage, since extra weight makes the senior years harder on the joints, breathing and heart. For stage-by-stage portions see the Shih Tzu nutrition and feeding guide, and for coat and skin routines see the Shih Tzu grooming guide.

If you notice pain, confusion, sudden weight loss, or difficulty walking, talk to your vet. These are not things to write off as “just old age.”

Final Thoughts

A Shih Tzu age chart helps you quickly understand your dog’s age in human years, but it should be treated as an estimate. Your dog’s real health and life stage also depend on weight, genetics, diet, activity level, dental care, and regular vet support.

Use this chart as a simple guide, then check your dog’s exact result with the Shih Tzu dog age calculator if you want an instant conversion.

Frequently Asked Questions

How old is a Shih Tzu in human years?

A Shih Tzu’s age in human years depends on their life stage. A 1-year-old Shih Tzu is about 15 human years old, a 2-year-old Shih Tzu is about 24 human years old, and after age 2 most Shih Tzus age by about 4 human years for each dog year.

How old is my Shih Tzu in human years?

You can estimate your Shih Tzu’s human age by using the age chart above. Find your dog’s age in the first column, then compare it with the human age equivalent. For a faster input-based result, use the Shih Tzu dog age calculator.

How old is a 6-month-old Shih Tzu in human years?

A 6-month-old Shih Tzu is roughly 10 human years old. Puppies age fastest in this first stretch, which is why the first year alone is worth about 15 human years.

How old is a 5-year-old Shih Tzu in human years?

A 5-year-old Shih Tzu is about 36 years old in human years. At this age, most Shih Tzus are still adults and may have steady energy with proper food, exercise, and care.

Is a 7-year-old Shih Tzu considered old?

A 7-year-old Shih Tzu is not usually considered very old. In human years, a 7-year-old Shih Tzu is about 44 years old. This is usually still an adult stage, although some dogs may start showing early signs of slowing down.

How old is a 10-year-old Shih Tzu in human years?

A 10-year-old Shih Tzu is about 56 years old in human years. This is usually the age when many Shih Tzus begin entering the senior life stage.

Is a 10-year-old Shih Tzu considered old?

Yes, 10 years old is usually considered senior age for a Shih Tzu. Many Shih Tzus can still be active at this age, but they may need more careful monitoring, gentler exercise, and regular vet checkups.

How old is a 12-year-old Shih Tzu in human years?

A 12-year-old Shih Tzu is about 64 years old in human years. At this age, your dog may need more comfort, dental care, joint support, and closer health monitoring.

How old is a 13-year-old Shih Tzu in human years?

A 13-year-old Shih Tzu is about 68 years old in human years. This is right around the breed’s average lifespan, so many Shih Tzus at this age are comfortable seniors who simply need a gentler routine.

How old is a 14-year-old Shih Tzu in human years?

A 14-year-old Shih Tzu is about 72 years old in human years. This is a senior age, so comfort, gentle movement, routine vet care, and a stable daily routine become more important.

How old is a 15-year-old Shih Tzu in human years?

A 15-year-old Shih Tzu is about 76 years old in human years. Reaching 15 puts your dog near the top of the breed’s typical lifespan range, and many at this age are still alert and affectionate with the right support.

How old is a 16-year-old Shih Tzu in human years?

A 16-year-old Shih Tzu is about 80 years old in human years. This is an advanced age for the breed, though it is still within the normal Shih Tzu lifespan range of 10 to 16 years.

Is 8, 12, 13 or 14 old for a Shih Tzu?

An 8-year-old Shih Tzu (about 48 in human years) is a mature adult, not yet a senior. At 12 (about 64) and 13 (about 68) a Shih Tzu is solidly senior but often still active. At 14 (about 72) your dog is on the older end of the breed’s typical range, and many Shih Tzus live comfortably past it.

How long do Shih Tzus live in human years?

Most Shih Tzus live 10 to 16 years, with about 13 years being typical. Using this chart, a 13-year lifespan works out to roughly 68 human years, and a Shih Tzu that reaches 16 is about 80 in human years.

When is a Shih Tzu considered a senior?

Most Shih Tzus are considered senior dogs around age 10. Some may slow down earlier or later depending on genetics, weight, activity level, and overall health.

When is a Shih Tzu full grown?

Most Shih Tzus reach their full adult height and weight between 9 and 12 months, though some fill out in the chest until around 18 months. By their first birthday, a Shih Tzu is physically grown but still behaves much like a teenager.

At what age do Shih Tzus slow down?

Many Shih Tzus start slowing down between 8 and 10 years old, but this varies by dog. Some remain playful into their senior years, while others may need gentler routines earlier.

Why is the 7-year rule wrong for Shih Tzus?

The 7-year rule is inaccurate because dogs age quickly in the first two years and then slow down. Small breeds like Shih Tzus usually live longer than large dogs, so one fixed rule does not match their aging pattern well.

Do Shih Tzus age slower than other dogs?

Shih Tzus usually age slower than large dog breeds after the first couple of years. Like many small dogs, they often have a longer lifespan and may stay active later into life with proper care.

How old is a Maltese Shih Tzu in human years?

A Maltese Shih Tzu mix ages on roughly the same small-breed schedule as a purebred Shih Tzu, so this chart applies. A 1-year-old is about 15 in human years, and each year after age 2 adds about 4.

More Shih Tzu Resources

Use these related Shih Tzu resources for topics that are covered in more detail on their dedicated pages:

• Shih Tzu Cost of Ownership Guide