How old is a 4-year-old dog in human years?

A 4-year-old dog is about

32–37

in human years, depending on size

Adult2–6 years

Settled, fit, and at their peak. Regular exercise and yearly vet checks keep them there.

What 4 years means for a dog

A 4-year-old dog is about 32 to 37 in human years. A small dog comes out at 32 and a giant dog at 37. If you're not sure which size your dog counts as, medium (21 to 50 lb or 10 to 23 kg) is a fair middle guide, at 33.

Bigger dogs age faster after the first two years, which is why the numbers spread out as dogs get older. The life stage shown above is for a medium dog.

4-year-old dogs by size

4-year-old dogWeightHuman yearsLife stage
SmallUp to 20 lb (9 kg)32Adult
Medium21–50 lb (10–23 kg)33Adult
Large51–90 lb (23–41 kg)35Adult
GiantOver 90 lb (41 kg)37Adult

Check any other age

Dog size

Common questions

How old is a 4-year-old dog in human years?

A 4-year-old dog is about 32 to 37 in human years. A small dog comes out at 32 and a giant dog at 37.

Do small dogs live longer than big dogs?

Generally, yes. Larger dogs tend to age faster and have shorter lives, which is why the chart gives bigger dogs a higher human age at the same calendar age.

How do I know which size my dog is?

Go by adult weight: small is up to 20 lb (9 kg), medium is 21 to 50 lb (10 to 23 kg), large is 51 to 90 lb (23 to 41 kg), and giant is over 90 lb (41 kg).

Nearby ages

See the full dog years to human years chart, or compare with a 4-year-old cat.