Breed size changes everything after age 2. At 10 years, a small breed is about 56 in human years, a medium breed 60, a large breed 66 and a giant breed 79.
Why breed matters for dog years
The "one dog year = seven human years" rule treats a Chihuahua and a Great Dane the same — but they age very differently. Every dog races through the first two years (about 15 human years at age 1 and 24 at age 2). After that, size and breed decide how fast a dog ages: small breeds add about 4 human years per year, while giant breeds add 7 or more. That's why the AKC and AVMA use size-based charts, and why a breed-specific calculator gives a far better answer.
This dog age calculator by breed covers 35+ popular breeds and four mixed-breed size groups. Pick a breed and it applies the right size curve, the breed's typical life expectancy from the American Kennel Club, and the AAHA life stage (puppy, young adult, mature adult or senior).
Dog years to human years chart by size
| Size | 1 yr | 3 yrs | 5 yrs | 8 yrs | 10 yrs | 12 yrs | 15 yrs |
|---|---|---|---|---|---|---|---|
| Small | 15 | 28 | 36 | 48 | 56 | 64 | 76 |
| Medium | 15 | 28 | 36 | 51 | 60 | 69 | 83 |
| Large | 15 | 28 | 36 | 55 | 66 | 77 | 93 |
| Giant | 12 | 31 | 45 | 64 | 79 | 93 | 114 |
Dog breeds and life expectancy
| Breed | Size | Life expectancy | Age 5 in human yrs | Age 10 in human yrs | Senior from (yrs) |
|---|---|---|---|---|---|
| Australian Shepherd | Medium | 12–15 yrs | 36 | 60 | 10.1 |
| Beagle | Medium | 10–15 yrs | 36 | 60 | 9.4 |
| Bernese Mountain Dog | Giant | 7–10 yrs | 45 | 79 | 6.4 |
| Bichon Frise | Small | 14–15 yrs | 36 | 56 | 10.9 |
| Border Collie | Medium | 12–15 yrs | 36 | 60 | 10.1 |
| Boston Terrier | Small | 11–13 yrs | 36 | 56 | 9 |
| Boxer | Large | 10–12 yrs | 36 | 66 | 8.3 |
| Bulldog | Medium | 8–10 yrs | 36 | 60 | 6.8 |
| Cavalier King Charles Spaniel | Small | 12–15 yrs | 36 | 56 | 10.1 |
| Chihuahua | Small | 15–17 yrs | 36 | 56 | 12 |
| Cockapoo | Small | 12–15 yrs | 36 | 56 | 10.1 |
| Cocker Spaniel | Medium | 13–15 yrs | 36 | 60 | 10.5 |
| Dachshund | Small | 12–16 yrs | 36 | 56 | 10.5 |
| Doberman Pinscher | Large | 10–12 yrs | 36 | 66 | 8.3 |
| French Bulldog | Small | 10–12 yrs | 36 | 56 | 8.3 |
| German Shepherd | Large | 7–10 yrs | 36 | 66 | 6.4 |
| Golden Retriever | Large | 10–12 yrs | 36 | 66 | 8.3 |
| Great Dane | Giant | 8–10 yrs | 45 | 79 | 6.8 |
| Havanese | Small | 14–16 yrs | 36 | 56 | 11.3 |
| Jack Russell Terrier | Small | 12–14 yrs | 36 | 56 | 9.8 |
| Labrador Retriever | Large | 11–14 yrs | 36 | 66 | 9.4 |
| Maltese | Small | 12–15 yrs | 36 | 56 | 10.1 |
| Miniature Poodle | Small | 12–15 yrs | 36 | 56 | 10.1 |
| Pit Bull | Medium | 12–14 yrs | 36 | 60 | 9.8 |
| Pomeranian | Small | 14–16 yrs | 36 | 56 | 11.3 |
| Pug | Small | 13–15 yrs | 36 | 56 | 10.5 |
| Rottweiler | Large | 10–12 yrs | 36 | 66 | 8.3 |
| Shih Tzu | Small | 10–18 yrs | 36 | 56 | 10.5 |
| Siberian Husky | Medium | 12–14 yrs | 36 | 60 | 9.8 |
| Standard Poodle | Medium | 12–15 yrs | 36 | 60 | 10.1 |
| Toy Poodle | Small | 12–15 yrs | 36 | 56 | 10.1 |
| Yorkipoo | Small | 12–15 yrs | 36 | 56 | 10.1 |
| Yorkshire Terrier | Small | 11–15 yrs | 36 | 56 | 9.8 |
"Senior from" is the start of the last 25% of the average lifespan, following the 2019 AAHA Canine Life Stage Guidelines.
Breed-specific calculators
Want a full chart for one breed? Open a dedicated calculator: Shih Tzu · Chihuahua · Golden Retriever · German Shepherd · Husky · Yorkie · Pit Bull · Poodle · Pomeranian · Labrador Retriever · Beagle · Dachshund · Pug · Cockapoo · Border Collie · Jack Russell Terrier · Cavalier King Charles.
How the breed calculator works
- Size curve: each breed is mapped to small (<20 lb), medium (21–50 lb), large (51–100 lb) or giant (100+ lb) and converted with the AKC/AVMA chart.
- Puppies: ages under 1 year use veterinary life-stage milestones (about 10 human years at 6 months).
- Lifespan & stage: the breed's typical life expectancy sets the "life journey" bar and the senior threshold.
- DNA formula for comparison: we also show the 2020 UC San Diego epigenetic formula, 16 × ln(age) + 31, which was developed in Labrador Retrievers.
Frequently asked questions
How do you calculate dog years by breed?
Find your breed's size group, then use a size-based chart: every dog is about 15 at age 1 and 24 at age 2; after that small breeds add about 4 human years per year, medium about 5, large about 5–6 and giant about 7. The calculator above also adds breed lifespan and life stage.
Which dog breeds live the longest?
Small breeds usually live longest. AKC data lists Chihuahuas at 15–17 years and Pomeranians at 14–16, while giant breeds such as Great Danes typically live 8–10 years.
How old is a 10 year old dog in human years by size?
A 10-year-old small dog is about 56, a medium dog about 60, a large dog about 66 and a giant dog about 79 in human years.
What is the dog years to human years chart by breed?
It's a table that converts dog age to human age using the breed's size group. See the charts above for size-based values and the breed list with life expectancy and senior age.
Is there a cat age calculator by breed?
Cats vary much less by breed than dogs, so vets use one feline chart for most cats. For breed details, try the Maine Coon age calculator (with the Maine Coon lifespan calculator) the Ragdoll age calculator (with the Ragdoll lifespan and Ragdoll growth chart tools) or the Siamese cat age calculator, or use the senior cat age calculator for any older cat.
Why do big dogs die younger?
Researchers think large dogs grow and age faster at the cellular level, which raises the risk of age-related diseases like cancer earlier in life. The exact reasons are still being studied.
This calculator gives an estimate for education and fun. Every pet ages differently — for health decisions, talk to your veterinarian.