Free pet age calculator

Pet Age Calculator: Pet Years to Human Years

Convert your dog's, cat's or small pet's age to human years. Dogs use the AAHA size chart, cats use the International Cat Care and VCA scale, and other pets use a clearly labelled proportional estimate.

  • Dogs by size, cats on the vet scale
  • Ferrets, guinea pigs, rabbits, hamsters and more
  • Honest about where no accepted conversion exists

🐾Pet age calculator

Pick your pet and enter an age.

Pet
Dog size (adult weight)

Your result

DogsAAHA size chart
CatsICC and VCA scale
10 small petsProportional estimate
FreeNo sign-up

How it works

How to use the pet age calculator

  1. Choose Dog, Cat or Other pet.
  2. Enter the age in years and months. For a dog, pick the size band that matches the adult weight.
  3. Read the human-year estimate and the extra figures underneath.
  4. For a dog or cat, open the full tool for more detail: the dog age calculator shows three methods and life stage, and the cat age chart explains the cat scale.

Two kinds of answer

What is science and what is estimate

For dogs the calculator uses the AAHA size chart, with 15 human years at age 1 and 24 at age 2 for every size, then separate columns for small, medium, large and giant dogs. For cats it uses the figures International Cat Care and VCA publish: 15 at age 1, 24 at age 2 and 4 more human years for every year after, with 6 months about 10.

For other pets there is no widely accepted conversion, and published lifespans disagree: PetMD gives hamsters 12 to 18 months while other sources say 2 to 3 years. So we do something simple and say so. We take the midpoint of PetMD's typical lifespan for the species, work out what share of that your pet has lived and scale it to an 80-year human life. It tells you roughly where your pet is in its life, not what birthday it would have.

PetTypical lifespan in years (PetMD)
Ferret6 to 9
Guinea pig4 to 6
Hamster1 to 1.5
Rat2 to 3
Rabbit, smaller breeds12 to 14
Rabbit, larger breeds4 to 6
Chinchilla10 to 12
Hedgehog1.5 to 2
Duck12 to 15
Leopard gecko15 to 20

From a PetMD article by Sandra C. Mitchell, DVM, published Jan 24, 2019. Other sources give different ranges, which is why these conversions are rough.

Beyond the number

What to do with your pet's age

Age drives food, vet visits and weight targets. Use our calorie calculator and food calculator for the right portion, the weight tracker to follow the trend, and the vaccination schedule to see what to book.

Questions

Frequently asked questions

How do I convert my pet's age to human years?
Choose your pet above and enter the age. Dogs and cats use published scales; other pets get a proportional estimate.
How old is a 1-year-old dog or cat in human years?
About 15 human years on the AAHA and vet scales for both species.
How old is a 10-year-old dog?
On the AAHA chart, about 56 for a small dog, 60 for a medium dog, 66 for a large dog and 78 for a giant dog.
How old is a 10-year-old cat?
About 56 human years on the International Cat Care and VCA scale.
Is there an age chart for rabbits, ferrets or hamsters?
There is no standard chart. Our estimate scales your pet's age to a typical lifespan from PetMD, so treat it as a rough position in life.
Why do the numbers differ between sites?
Different sites use different formulas. We name ours: AAHA for dogs, International Cat Care and VCA for cats.

Keep going

More tools for your pet

ToolDog age calculatorThree methods, size bands and life stage.ToolDog & cat food calculatorDaily food for your pet's age.ToolPet weight trackerLog weight over time.

Read next

Related guides

GuideCat years to human years: the real age chartThe cat scale with a calculator.GuideDog age chart: how old is your dog in human yearsThe full dog chart.GuideGuinea pig care: a complete guideLifespan, diet and housing.

Sources

Where the numbers come from

Estimates for interest and planning only; not veterinary advice. Last reviewed October 2026.

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