Dog Age Calculator
Enter your dog’s birthday to get its exact age in years, months and days, its next birthday, its life stage (puppy, young adult, mature adult or senior) and its age in human years on the AKC chart.
Senior age depends on size: the AVMA puts it at about 8–11 years for small dogs and 6–7 years for giant breeds.
How it works
Life stages follow the 2019 AAHA Canine Life Stage Guidelines: puppy (until rapid growth ends, about 6–9 months), young adult (until physical and social maturity, usually 3–4 years), mature adult (until the last 25% of the expected lifespan), senior (the last 25%), and end of life (any age).
When the senior years start: if you pick a breed, we take 75% of the AKC life expectancy range (for example 11–13 years → about 8.3–9.8 years). If you pick a size, we use the AVMA’s senior ages: small 8–11, medium 8–10, large 8–9, giant 6–7 years.
Human years come from the AKC chart, with the Wang et al. (2020) epigenetic clock for comparison. Dogs born on 29 February celebrate on 28 February in non-leap years here.
How to use it
- Pick the birthday. Or switch to entering the age in years and months.
- Choose the breed or size. With a breed, the senior age uses the last 25% of the breed’s AKC life expectancy.
- Read the results. Exact age, next birthday countdown, life stage and human years.
Dog life stages
| Stage | When |
|---|---|
| Puppy | Birth until rapid growth ends (about 6–9 months, varies by size) |
| Young adult | Until physical and social maturity (usually 3–4 years) |
| Mature adult | Until the last 25% of the expected lifespan |
| Senior | The last 25% of the expected lifespan |
| End of life | Any age (terminal stage) |
When the senior years start
| Size | Senior from about |
|---|---|
| Small (under 20 lb / 9 kg) | 8–11 years |
| Medium (20–50 lb / 9–23 kg) | 8–10 years |
| Large (50–90 lb / 23–41 kg) | 8–9 years |
| Giant (over 90 lb / 41 kg) | 6–7 years |
Stages: 2019 AAHA Canine Life Stage Guidelines. Senior ages: AVMA. AVMA size bands differ slightly from the AKC age chart.
Frequently asked questions
How do I calculate my dog’s age?
Count the full years and months since the birthday. The calculator does this for you, including leap years, and shows the days until the next birthday.
When is a dog considered a senior?
AAHA defines senior as the last 25% of the expected lifespan. The AVMA gives typical senior ages by size: small dogs (under 20 lb) 8–11 years, medium (20–50 lb) 8–10, large (50–90 lb) 8–9 and giant (over 90 lb) 6–7.
What are the dog life stages?
Puppy, young adult, mature adult, senior and end of life (2019 AAHA Canine Life Stage Guidelines). Puppyhood ends when rapid growth stops, usually around 6–9 months.
How old is my dog in human years?
See the result above, or the dog years to human years chart. A 10-year-old medium dog is about 60 in human years on the AKC chart.
What if I don’t know my dog’s birthday?
Use your best guess or the age your shelter or vet estimated, and switch to the years-and-months option.
When to see a vet
- Your dog is entering the senior years: ask about senior wellness check-ups.
- Changes in weight, appetite, thirst, mobility, sight, hearing or behaviour.
- You are unsure of your dog’s age: a vet can estimate it from teeth and other signs.
This is an estimate for general information, not veterinary advice. Every pet is different. Ask your veterinarian before changing your pet's diet, especially for puppies, kittens, pregnant or nursing pets, seniors, or pets with health conditions.
Sources
- AAHA. 2019 AAHA Canine Life Stage Guidelines: Canine life stage definitions. www.aaha.org/resources/life-stage-canine-2019/canine-life-stage-definitions/
- American Veterinary Medical Association. Senior pets. www.avma.org/resources-tools/pet-owners/petcare/senior-pets
- American Kennel Club. How to Calculate Dog Years to Human Years (dog age chart by size). www.akc.org/expert-advice/health/how-to-calculate-dog-years-to-human-years/
- American Kennel Club. Dog breed pages (breed-standard height, weight and life expectancy), accessed 20 October 2026. www.akc.org/dog-breeds/
- Wang T, Ma J, Hogan AN, et al. Quantitative Translation of Dog-to-Human Aging by Conserved Remodeling of the DNA Methylome. Cell Systems. 2020;11(2):176–185. doi.org/10.1016/j.cels.2020.06.006
Full methodology: sources and methodology. Last reviewed 20 October 2026.