How old would your dog or cat be if it were a person? The "multiply by 7" rule is a myth: pets age very quickly in their first two years and then more slowly, at a pace that depends on their size. Use the calculator below to find out your pet's age in human years and which life stage it is in.
Why isn't it just multiplying by 7?
A dog's or cat's first year equals about 15 human years: in that time it goes from baby to teenager. The second year adds about 9 more. After that, each year is worth 4 to 7 human years, depending on size. Large and giant dogs age faster and usually live shorter lives than small dogs.
Dog age in human years chart
| Dog's age | Small (up to 22 lb) | Medium (23–55 lb) | Large (56–100 lb) | Giant (100+ lb) |
|---|---|---|---|---|
| 1 year | 15 | 15 | 15 | 12 |
| 2 years | 24 | 24 | 24 | 22 |
| 3 years | 28 | 28 | 28 | 31 |
| 4 years | 32 | 32 | 32 | 38 |
| 5 years | 36 | 36 | 36 | 45 |
| 6 years | 40 | 42 | 45 | 49 |
| 7 years | 44 | 47 | 50 | 56 |
| 8 years | 48 | 51 | 55 | 64 |
| 9 years | 52 | 56 | 61 | 71 |
| 10 years | 56 | 60 | 66 | 79 |
| 11 years | 60 | 65 | 72 | 86 |
| 12 years | 64 | 69 | 77 | 93 |
| 13 years | 68 | 74 | 82 | 100 |
| 14 years | 72 | 78 | 88 | 107 |
| 15 years | 76 | 83 | 93 | 114 |
| 16 years | 80 | 87 | 99 | 121 |
Cat age in human years chart
| Cat's age | Human age |
|---|---|
| 1 year | 15 |
| 2 years | 24 |
| 3 years | 28 |
| 4 years | 32 |
| 5 years | 36 |
| 6 years | 40 |
| 7 years | 44 |
| 8 years | 48 |
| 9 years | 52 |
| 10 years | 56 |
| 11 years | 60 |
| 12 years | 64 |
| 13 years | 68 |
| 14 years | 72 |
| 15 years | 76 |
| 16 years | 80 |
| 17 years | 84 |
| 18 years | 88 |
| 19 years | 92 |
| 20 years | 96 |
Values are approximate and follow the reference charts used by veterinary associations. Breed, genetics, diet and care all influence how each animal ages.
Your pet's life stages
- Puppy/kitten: up to 1 year (giant dogs up to about 18 months). The stage of growth, vaccines and socialization.
- Young adult: full of energy, needs daily exercise and stimulation.
- Adult: keep up yearly checkups, vaccines and weight control.
- Senior: starts around 7 to 10 years in dogs (earlier in large breeds) and around 11 years in cats. Checkups every 6 months help detect diseases early.
- Geriatric: a stage that calls for more comfort, a suitable diet and frequent vet visits.
Frequently asked questions
How old is a 10-year-old dog in human years?
It depends on size: about 56 for a small dog, 60 for a medium dog, 66 for a large dog and 79 for a giant dog.
How old is a 15-year-old cat in human years?
About 76 human years. Well-cared-for cats often live past 15.
When is a pet considered a senior?
Small dogs at around 10 years, medium dogs at 8, large dogs at 7 and giant dogs at 6. Cats at around 11 years.
For information only. This does not replace an assessment by a veterinarian, who knows your pet's health and routine.