Cat and dog age in human years

Cats and dogs age completely differently from us: fast in the first year or two, then more slowly, and the bigger the animal the faster it usually ages. Enter your pet's real age to see the equivalent human age, which life stage it is in, and what checks that stage calls for.

Pet age converter

How old is your pet in human years? Enter its real age for an instant conversion, plus its life stage. Everything is calculated in your browser — nothing is uploaded.

Pet type

Actual age: 3 years

How the conversion works

Cat: the first year equals 15 human years, the second year equals 24, then each extra year adds 4.

Dog: from 1 year old the epigenetic formula applies (human years = 16 × ln(dog age) + 31), which is why small dogs convert as ageing more slowly than large dogs.

Results

Actual age → human equivalent age → life stage

Cat 3 years

Roughly equal to a human aged

28 years

Life stage: Adult cat

Cat age reference

6 months≈ 8 years
1 years≈ 15 years
2 years≈ 24 years
5 years≈ 36 years
11 years≈ 60 years
16 years≈ 80 years

What to watch at this stage

For adults: keep an ideal body shape (ribs easy to feel, a visible waist) and have a health and dental check once a year.

These figures are general reference values calculated with standard veterinary nutrition formulas. They are for guidance only and cannot replace a veterinary diagnosis or prescription. If your pet is unwell, pregnant or nursing, recovering from surgery, still growing, or has breed-specific needs, follow your vet's advice and the label on the food or product, and adjust the portion to your pet's body condition score.

Choose food by life stage (product matcher) →|Work out daily feeding amount

Conversion formula (fully disclosed)

Cats: under 1 year the conversion is linear at 15 × age; 1 year = 15, 2 years = 24; then each extra year adds 4 (an 11-year-old cat is about 60 human years).
Dogs: from 1 year old the epigenetic formula applies, 16 × ln(dog age) + 31 (1 year is about 31, 5 years about 57, 10 years about 68 human years).
Life stage: cats from 11 years and dogs from 8 years count as senior; under 4 months and 4-12 months are the early and later young stages.

Frequently Asked Questions

These figures are general reference values from a widely used veterinary ageing model. They are for guidance only and cannot replace a veterinary diagnosis or prescription. The rate of ageing depends on breed, body size and health, so your vet's assessment comes first.

Want to choose food by life stage? Filter young, senior and weight-management formulas with the product matcher →

Further reading: Daily feeding calculator|Daily water intake calculator|Health category guide