How to use the dog age calculator
- Pick the size: small dogs age slower than large dogs after the first two years.
- Enter the birth date. If you only know the year, use 1 January.
- Read the age in years and months, the human age and the life stage.
How it is worked out
- First year = 15 human years
- Second year adds 9 more (24 at age 2)
- Each year after that adds 4 (small), 5 (medium) or 7 (large) human years
Dog age in human years by size
| Dog age | Small, under 10 kg | Medium, 10 to 25 kg | Large, over 25 kg |
|---|---|---|---|
| 1 year | 15 | 15 | 15 |
| 2 years | 24 | 24 | 24 |
| 3 years | 28 | 29 | 31 |
| 5 years | 36 | 39 | 45 |
| 7 years | 44 | 49 | 59 |
| 10 years | 56 | 64 | 80 |
| 12 years | 64 | 74 | 94 |
| 15 years | 76 | 89 | 115 |
| 18 years | 88 | 104 | 136 |
Frequently asked questions
How do you convert dog years to human years?
Puppies grow up fast, so the first two years count for much more than later ones. After that each year adds a smaller, steady amount. The table above shows the full conversion.
Is the old "multiply by 7" rule right?
No. It makes young animals look too young and old animals look too old. A two stage formula like the one here is much closer to how they actually age.
How accurate is this?
Human years are an estimate for planning and fun. Breed, size, diet and care all change how an animal ages. Ask your vet about senior health checks.
Is my data saved?
No. The birth date stays in your browser and is not stored or sent.
Disclaimer: Results are estimates for planning only. They are not veterinary advice. Talk to your vet about your own animal's health, diet and weight.
