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Dog age calculator: dog years to human years

Convert your dog’s age into human years and see their life stage, with a chart from 1 to 18 years.

Estimated life stage

Rough human-age comparison
39 years
Life stage
Adult

This is only a broad estimate. Breed, body size, lifestyle and health history can all affect how your pet ages.

If your dog is slowing down, losing weight, eating differently or behaving differently, book a check-up rather than assuming it is simply getting older.

Dog years to human years chart

Find your dog’s age in the left-hand column to see the rough equivalent in human years and life stage for each size of dog.

Dog’s age Small dog under 10 kg Medium dog 10 to under 25 kg Large dog 25 to under 45 kg Giant dog 45 kg or more
1 year 15 Young adult 15 Young adult 15 Young adult 15 Young adult
2 years 24 Young adult 24 Young adult 24 Young adult 24 Young adult
3 years 28 Adult 29 Adult 30 Adult 31 Adult
4 years 32 Adult 34 Adult 36 Adult 38 Adult
5 years 36 Adult 39 Adult 42 Adult 45 Adult
6 years 40 Adult 44 Adult 48 Adult 52 Senior
7 years 44 Adult 49 Adult 54 Senior 59 Senior
8 years 48 Senior 54 Senior 60 Senior 66 Senior
9 years 52 Senior 59 Senior 66 Senior 73 Senior
10 years 56 Senior 64 Senior 72 Senior 80 Senior
11 years 60 Senior 69 Senior 78 Senior 87 Senior
12 years 64 Senior 74 Senior 84 Senior 94 Senior
13 years 68 Senior 79 Senior 90 Senior 101 Senior
14 years 72 Senior 84 Senior 96 Senior 108 Senior
15 years 76 Senior 89 Senior 102 Senior 115 Senior
16 years 80 Senior 94 Senior 108 Senior 122 Senior
17 years 84 Senior 99 Senior 114 Senior 129 Senior
18 years 88 Senior 104 Senior 120 Senior 136 Senior

How to use it

How the pet age calculator works

Enter your pet’s age and, for a dog, their size. Dogs and cats grow up quickly: their first year is roughly 15 human years and their second about 9 more. After that a cat adds about 4 human years a year, and a dog between 4 and 7 depending on size, because larger breeds age faster. Rabbits and horses use simpler estimates.

Treat the result as a prompt to think about your pet’s care, not as a diagnosis. Two animals born on the same day can age very differently. What matters most is whether you have noticed changes in their weight, movement, appetite, thirst, toilet habits or behaviour.

What the result means

  • For a young animal, ask your vet about growth, vaccinations, parasite prevention, socialisation and neutering.
  • For an adult animal, keep an eye on weight and dental health, stay up to date with parasite prevention, and learn what is normal for them.
  • For a mature or senior animal, watch for changes in weight, movement, teeth, thirst, appetite, toilet habits or behaviour, and consider check-ups every six months.
  • For a horse, age is only part of the picture. Workload, teeth, hoof care, body condition and signs of stiffness also matter.

Changes to discuss with your vet

Contact your vet if your pet slows down suddenly, gains or loses weight without an obvious reason, drinks more, seems stiff, eats differently, develops bad breath, coughs, hides, becomes unsettled or stops enjoying their usual activities. Don’t assume a change is simply part of getting older.

Common questions

How old is a 1-year-old dog in human years?

About 15, whatever the dog’s size. Dogs grow up fast in their first two years; after that, larger dogs age faster than smaller ones.

How old is a 2-year-old dog in human years?

About 24, whatever the dog’s size. Dogs grow up fast in their first two years; after that, larger dogs age faster than smaller ones.

How old is a 7-year-old dog in human years?

About 44 for a small dog, 49 for a medium dog, 54 for a large dog and 59 for a giant breed. Larger dogs age faster after their second year, so a 7-year-old giant breed is older in human terms than a small dog of the same age.

How old is a 10-year-old dog in human years?

About 56 for a small dog, 64 for a medium dog, 72 for a large dog and 80 for a giant breed. Larger dogs age faster after their second year, so a 10-year-old giant breed is older in human terms than a small dog of the same age.

How old is a 14-year-old dog in human years?

About 72 for a small dog, 84 for a medium dog, 96 for a large dog and 108 for a giant breed. Larger dogs age faster after their second year, so a 14-year-old giant breed is older in human terms than a small dog of the same age.

At what age is a dog a senior?

Giant breeds are often considered senior from about 6, large dogs from 7 and small and medium dogs from about 8. Many vets suggest check-ups every six months from then.

Is one pet year the same as seven human years?

No. It is a popular shortcut, but animals don’t age at a fixed rate. Dogs and cats mature quickly in their first two years, then age more slowly, and large dogs age faster than small ones.

Why does dog size change the result?

Larger dogs tend to have shorter lifespans and often reach their senior years earlier than smaller dogs. The calculator uses size to reflect that broad difference.

Does the calculator diagnose health problems?

No. It gives a rough life-stage estimate. It can’t explain symptoms or replace a veterinary examination.

Use the result as a starting point

These tools are planning aids, not a diagnosis or a replacement for veterinary advice. If a pet is unwell, has eaten something risky, or you are unsure what to do next, contact a vet.

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