Quick answer: how old is a medium dog in human years?
A 1-year-old medium dog is about 15 human years old. A 2-year-old medium dog is about 24 human years old. After age 2, medium dogs usually add about 4 to 5 human years for each additional dog year.
- A 5-year-old medium dog is about 38 human years old.
- A 7-year-old medium dog is about 47 human years old.
- A 10-year-old medium dog is about 60 human years old.
- A 12-year-old medium dog is about 69 human years old.
- A 14-year-old medium dog is about 78 human years old.
The old "one dog year equals seven human years" rule is too simple. Dogs grow quickly during the first two years, and after that, age estimates depend more on body size and breed. AKC and PetMD both explain that dog age is not a straight 7-year formula and that size matters when estimating dog years to human years.
Medium Dog Age Chart
Use this chart as a general guide for medium dog years to human years.
Swipe the table sideways to see all columns.
| Dog age | Human age | Life stage |
|---|---|---|
| 3 months | About 5 human years | Puppy |
| 6 months | About 10 human years | Puppy |
| 9 months | About 14 human years | Puppy / Young dog |
| 1 year | About 15 human years | Young adult |
| 2 years | About 24 human years | Adult |
| 3 years | About 29 human years | Adult |
| 4 years | About 33 human years | Adult |
| 5 years | About 38 human years | Adult |
| 6 years | About 42 human years | Adult / Mature adult |
| 7 years | About 47 human years | Mature adult |
| 8 years | About 51 human years | Mature adult / Senior |
| 9 years | About 56 human years | Senior |
| 10 years | About 60 human years | Senior |
| 11 years | About 65 human years | Senior |
| 12 years | About 69 human years | Senior |
| 13 years | About 74 human years | Senior |
| 14 years | About 78 human years | Senior |
| 15 years | About 83 human years | Very senior |
| 16 years | About 87 human years | Very senior |
| 17 years | About 92 human years | Very senior |
| 18 years | About 96 human years | Very senior |
| 19 years | About 101 human years | Very senior |
| 20 years | About 105 human years | Very senior |
Note: This chart is a general estimate for medium dogs. A Beagle, Border Collie, Australian Shepherd, Cocker Spaniel, Cavapoo, Corgi, Basenji, and Whippet may not age exactly the same way.
How Do Medium Dogs Age in Human Years?
Medium dogs grow quickly during puppyhood. By 1 year old, many medium dogs are close to young adult maturity. By 2 years old, many medium dogs are fully adult or close to fully mature.
After age 2, medium dogs usually age at a moderate pace compared with other size groups. They often age faster than toy and small dogs, but slower than large and giant dogs.
This is still an estimate, but it is more useful than multiplying every dog's age by 7.
A simple medium dog age model is:
- 1 year old = about 15 human years
- 2 years old = about 24 human years
- After age 2 = about 4 to 5 human years for each medium dog year
Why Medium Dog Age Is Different From Small and Large Dog Age
Dog size matters when calculating dog years to human years.
Toy and small dogs often live longer and may age more slowly after adulthood. Large and giant dogs usually age faster and may become seniors earlier. Medium dogs sit between these two groups.
This is why a medium dog age calculator should not use the exact same aging rate as a toy dog, small dog, large dog, or giant dog calculator.
PetMD explains that after age 2, one dog year can equal about 4 years for small dogs, 4 to 5 years for medium dogs, 5 to 6 years for large dogs, and 7 to 8 years for giant dogs.
For example:
- A 10-year-old small dog may be about 56 human years old.
- A 10-year-old medium dog may be about 60 human years old.
- A 10-year-old large dog may be closer to the late 60s in human years.
- A 10-year-old giant dog may be much older in life-stage terms.
Which Breeds Count as Medium Dogs?
Medium dogs are usually larger than small companion breeds but smaller than large working or sporting breeds. They often fall around the middle in weight, lifespan, and aging speed.
Common medium dog breeds include:
- Beagle
- Border Collie
- Australian Shepherd
- Cocker Spaniel
- English Cocker Spaniel
- Cavapoo
- Corgi
- Staffordshire Bull Terrier
- Basenji
- Whippet
- English Springer Spaniel
- American Eskimo Dog
- Australian Cattle Dog
- Keeshond
- Standard Schnauzer
- Soft Coated Wheaten Terrier
- Welsh Springer Spaniel
- Brittany
- Miniature American Shepherd
- Portuguese Water Dog
- Border Terrier
- Bull Terrier
- Chow Chow
- Shar Pei
- Cardigan Welsh Corgi
- Pembroke Welsh Corgi
Choosing the right size group
Some dogs can overlap between small, medium, or large depending on weight, build, and breed line. If you are not sure, choose the size group that best matches your dog's adult weight and body type.
Medium Dog vs Small Dog: What Is the Difference?
Small dogs are usually compact companion breeds, such as Shih Tzu, Pug, Dachshund, French Bulldog, Miniature Schnauzer, Bichon Frise, and Boston Terrier.
Medium dogs are usually sturdier and heavier than small dogs. Examples include Beagle, Border Collie, Australian Shepherd, Cocker Spaniel, Staffordshire Bull Terrier, Cavapoo, Corgi, and Whippet.
There is some overlap. A small Corgi or Cavapoo may feel closer to a small dog, while a larger Australian Shepherd may feel closer to a large dog. The calculator gives the best estimate when you choose the breed, but the size group is helpful if you do not know the exact breed.
Use the small dog age calculator if your dog is compact and under the small-dog range. Use the medium dog age calculator if your dog is in the middle range. Use the large dog age calculator if your dog is heavier, taller, or closer to large-breed size.
When Is a Medium Dog Considered Senior?
Many medium dogs are considered senior around 8 to 9 years old. Some medium dogs may start showing senior signs around 7 years old, while others stay active longer.
A medium dog's senior age can depend on:
- Breed
- Weight
- Dental health
- Activity level
- Diet
- Genetics
- Veterinary care
- Lifestyle
- Existing health conditions
AAHA senior life stage guidance
AAHA defines senior life stage as the last 25% of a dog's estimated lifespan, and it notes that life stage depends on breed, size, lifestyle, and health status.
Common signs of senior age in medium dogs include:
- Less energy
- Gray hair around the face
- Dental problems
- Cloudy eyes
- Hearing changes
- Joint stiffness
- Weight gain or weight loss
- More sleep
- Lower stamina
- Behavior changes
When to call your vet
If your dog suddenly changes behavior, appetite, movement, or energy level, speak with a veterinarian.
Older Medium Dogs: Age in Human Years
Is 7 Old for a Medium Dog?
A 7-year-old medium dog is not always "old," but many medium dogs are entering the mature adult stage around this age.
A 7-year-old medium dog is about 47 human years old. Some medium dogs at this age are still very active, while others may start showing early signs of aging.
At 7 years old, it is a good idea to pay more attention to:
- Weight
- Teeth and gums
- Joint comfort
- Energy level
- Stamina
- Sleep patterns
- Exercise tolerance
- Behavior changes
Preventive care at age 7
This does not mean your dog is unhealthy. It simply means your dog is no longer young, and preventive care becomes more important.
12-Year-Old Medium Dog in Human Years
A 12-year-old medium dog is about 69 human years old.
At this age, most medium dogs are seniors. Some may still be active and happy, while others may need more help with mobility, dental care, vision, hearing, or weight management.
Helpful care tips for a 12-year-old medium dog include:
- Schedule regular vet checkups
- Watch for appetite changes
- Keep exercise gentle but consistent
- Support dental health
- Monitor weight
- Provide soft bedding
- Watch for signs of pain or stiffness
- Keep routines predictable
Comfort and monitoring at age 12
A 12-year-old medium dog may still enjoy walks, play, training, and family time, but comfort and health monitoring become more important.
14-Year-Old Medium Dog in Human Years
A 14-year-old medium dog is about 78 human years old.
This is a very senior age for most medium dogs. A healthy 14-year-old medium dog may still enjoy a good quality of life, but owners should be more alert to age-related changes.
At this stage, it is helpful to watch:
- Mobility
- Teeth and gums
- Vision
- Hearing
- Sleep patterns
- Appetite
- Water intake
- Bathroom habits
- Mood and behavior
- Signs of discomfort
When to call your vet
Sudden changes should be discussed with a veterinarian.
Life stages
Puppy
Medium dog puppies grow quickly during the first year. Their body, teeth, behavior, and energy level change fast during this stage.
Young Adult
Medium dogs around 1 to 3 years old are usually young adults. Many are fully grown or close to fully grown, but their behavior and maturity may still be developing.
Adult
Medium dogs from around 3 to 6 years old are usually adults. This is the stage where healthy weight, exercise, dental care, training, and routine checkups matter most.
Mature Adult
Medium dogs around 6 to 8 years old may be mature adults. They are not always seniors yet, but owners should start watching for age-related changes.
Senior
Medium dogs around 8 to 9 years and older are often considered seniors. Many still live active lives at this age, but senior care becomes more important.
Very Senior
Medium dogs in their mid-to-late teens are very senior. At this stage, comfort, gentle exercise, routine veterinary support, and quality of life matter most.
How to help your dog age well
- Keep your dog at a healthy weight
- Use age-appropriate food
- Schedule routine veterinary checkups
- Care for your dog's teeth
- Keep exercise consistent
- Adjust activity as your dog gets older
- Watch for pain or stiffness
- Keep nails trimmed
- Provide mental enrichment
- Monitor behavior and appetite changes
- Use non-slip surfaces if your dog becomes unsteady
- Avoid sudden intense exercise in older dogs
- Medium dogs often enjoy activity, training, walks, play, and mental work. As they age, the goal is not to stop activity, but to adjust it to your dog's comfort and health.
Medium Dog Age Compared With Other Dog Sizes
A medium dog can be the same real age as a small or large dog but have a different human-age estimate.
- A 10-year-old toy or small dog may be about 56 human years old.
- A 10-year-old medium dog may be about 60 human years old.
- A 10-year-old large dog may be about 68 human years old.
- A 10-year-old giant dog may be much older in life-stage terms.
This is why dog age by size is important. If you want a broader comparison, use the dog age chart. If you know your dog's breed, use a breed-specific dog age calculator.
Related dog age calculators
- Dog Age Calculator
- Dog Age Chart
- Toy Dog Age Calculator
- Small Dog Age Calculator
- Large Dog Age Calculator
- Giant Dog Age Calculator
Breed calculators
Medium Dog Age Calculator FAQ
How do medium dogs age in human years?+
Medium dogs age quickly during the first two years. A 1-year-old medium dog is about 15 human years old, and a 2-year-old medium dog is about 24 human years old. After that, medium dogs usually add about 4 to 5 human years for each dog year.
What is a medium dog's age in human years?+
It depends on the dog's real age. For example, a 5-year-old medium dog is about 38 human years old, a 10-year-old medium dog is about 60 human years old, and a 14-year-old medium dog is about 78 human years old.
How do I calculate a medium dog's age in human years?+
Use the calculator at the top of this page. You can also estimate it manually by counting the first year as about 15 human years, the second year as about 24 total human years, and each year after that as about 4 to 5 more human years.
How old is a 7-year-old medium dog in human years?+
A 7-year-old medium dog is about 47 human years old. Many medium dogs at this age are mature adults and may be approaching the senior stage.
Is 7 old for a medium dog?+
A 7-year-old medium dog is not necessarily old, but it is no longer young. Many medium dogs around this age are mature adults, and some may start showing early signs of aging.
How old is a 12-year-old medium dog in human years?+
A 12-year-old medium dog is about 69 human years old. Most medium dogs at this age are seniors.
How old is a 14-year-old medium dog in human years?+
A 14-year-old medium dog is about 78 human years old. This is a very senior age for most medium-sized dogs.
Do medium dogs live longer than large dogs?+
Medium dogs often live longer than large and giant dogs, but not always as long as toy or small dogs. Breed, genetics, diet, weight, and healthcare can all affect lifespan.
Is a Beagle a medium dog?+
Yes, Beagles are usually considered medium dogs and can use medium dog age logic.
Is a Border Collie a medium dog?+
Yes, Border Collies are usually considered medium dogs, although some may be closer to large depending on size and weight.
Is an Australian Shepherd a medium dog?+
Most Australian Shepherds are medium-sized dogs, though some can be closer to large depending on build and weight.
Is a Corgi a medium dog?+
Corgis can overlap between small and medium. Many owners can use the medium dog calculator, but smaller Corgis may fit better under small dog age estimates.
Is the medium dog age chart exact?+
No. The chart is an estimate. Real aging can vary by breed, genetics, health, weight, dental care, activity level, and veterinary care.
The medium dog age calculator is designed to help you understand your dog's age in a more useful way than the old 7-year rule. The number matters, but the life stage matters more. A medium dog's age can help you understand whether your dog is a puppy, young adult, adult, mature adult, senior, or very senior.
Disclaimer: This page is for general information only. It is not veterinary advice. For health, diet, pain, dental, behavior, or aging concerns, speak with a qualified veterinarian.