Dog Years to Human Years Calculator
A dog’s first year equals about 15 human years and the second about 9 more, so a 2-year-old dog is about 24. After that it depends on size: a 10-year-old dog is about 56 in human years if small, 60 if medium, 66 if large and 79 if giant (AKC chart).
“Multiply by 7” is a myth. Dogs grow up very fast in the first two years, and larger dogs age faster after that.
How it works
We use the AKC chart “How old is my dog in human years?”, which lists human-equivalent ages for small, medium, large and giant dogs from 1 to 16 years. For ages between whole years we interpolate in a straight line between chart rows.
We also show the epigenetic clock from Wang et al. (2020), based on DNA methylation in 104 Labrador retrievers:
human age = 16 × ln(dog age in years) + 31 (for dogs 1 year and older)
The two methods disagree because they measure different things: the chart is a rule of thumb by size, while the clock tracks molecular ageing in one breed.
How to convert dog years to human years
- Enter your dog’s age. Years and months, or switch to the birthday option.
- Choose the breed or size. Small (20 lb or less), medium (21–50 lb), large (51–100 lb) or giant (over 100 lb).
- Read the human age. The calculator reads the AKC chart and fills in between whole years.
- Compare with the epigenetic clock. We also show 16 × ln(age) + 31 from a 2020 DNA-methylation study of Labradors.
Dog years to human years chart
| Dog age | Small ≤20 lb (≤9 kg) | Medium 21–50 lb (10–23 kg) | Large 51–100 lb (23–45 kg) | Giant 100+ lb (45+ kg) | Epigenetic clock* |
|---|---|---|---|---|---|
| 1 year | 15 | 15 | 15 | 12 | 31 |
| 2 years | 24 | 24 | 24 | 22 | 42 |
| 3 years | 28 | 28 | 28 | 31 | 49 |
| 4 years | 32 | 32 | 32 | 38 | 53 |
| 5 years | 36 | 36 | 36 | 45 | 57 |
| 6 years | 40 | 42 | 45 | 49 | 60 |
| 7 years | 44 | 47 | 50 | 56 | 62 |
| 8 years | 48 | 51 | 55 | 64 | 64 |
| 9 years | 52 | 56 | 61 | 71 | 66 |
| 10 years | 56 | 60 | 66 | 79 | 68 |
| 11 years | 60 | 65 | 72 | 86 | 69 |
| 12 years | 64 | 69 | 77 | 93 | 71 |
| 13 years | 68 | 74 | 82 | 100 | 72 |
| 14 years | 72 | 78 | 88 | 107 | 73 |
| 15 years | 76 | 83 | 93 | 114 | 74 |
| 16 years | 80 | 87 | 99 | 121 | 75 |
Chart: American Kennel Club. *16 × ln(age) + 31 (Wang et al. 2020, Labradors), rounded.
Frequently asked questions
How old is my dog in human years?
Use the AKC chart: 1 year ≈ 15 and 2 years ≈ 24 for small, medium and large dogs. After that, small dogs add about 4 years per year and larger dogs more. At 10 years, a small dog is about 56, medium 60, large 66 and giant 79.
Is one dog year equal to seven human years?
No. The AVMA and AKC both say the 7:1 ratio is not accurate. Dogs mature much faster in their first two years, and the rate after that depends on size.
Why do big dogs age faster?
Larger breeds tend to have shorter lives, so each year counts for more. The AVMA notes that giant breeds may be considered senior at 6–7 years, while small breeds may not be senior until 8–11.
What is the epigenetic clock formula?
A 2020 study (Wang et al., Cell Systems) compared DNA methylation in Labrador retrievers and people and found human age ≈ 16 × ln(dog age) + 31. A 10-year-old Labrador comes out at about 68.
How old is a 1-year-old dog in human years?
About 15 for small, medium and large dogs, and about 12 for giant dogs, on the AKC chart.
When to see a vet
- Your dog is approaching the senior years for its size: ask about senior check-ups.
- New lumps, weight change, stiffness, drinking more, or changes in behaviour or sleep.
- Your dog is slowing down suddenly rather than gradually.
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
- 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 Veterinary Medical Association. Senior pets. www.avma.org/resources-tools/pet-owners/petcare/senior-pets
- 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
- UC Davis School of Veterinary Medicine. Calculating Your Dog’s Age. healthtopics.vetmed.ucdavis.edu/health-topics/canine/calculating-your-dogs-age
- AAHA. 2019 AAHA Canine Life Stage Guidelines: Canine life stage definitions. www.aaha.org/resources/life-stage-canine-2019/canine-life-stage-definitions/
Full methodology: sources and methodology. Last reviewed 20 October 2026.