Is one dog year really seven human years?

No. The seven-to-one rule is a rough rule of thumb. A one-year-old dog is closer to a person in their early 30s than a seven-year-old child, and the formula on this page reflects that.

Does breed or size change the answer?

In life, yes: larger breeds tend to have shorter lives. The formula here comes from one breed, so treat it as a guide and ask your vet how your own dog is ageing.

Why is there nothing for a young puppy?

The formula is not reliable below about 3 months, when a puppy changes week to week. We would rather show nothing than a number that looks exact.

How old is your dog in human years?

Enter their age, or their date of birth. Nothing is stored anywhere but this browser.

A 5-year-old dog works out at about 57 in human years. The sum is 16 times the natural logarithm of 5, which is 25.8, plus 31. A 1-year-old comes out at 31 and a 12-year-old at about 71.

Dog age in human years
Dog age	Human years
6 months	20
1 year	31
2 years	42
3 years	49
4 years	53
5 years	57
6 years	60
7 years	62
8 years	64
9 years	66
10 years	68
12 years	71
14 years	73
16 years	75

Your dog

Years

Months

Or a date of birth

Fills the boxes above and is remembered on this device only.

In human years

Enter your dog's age and the answer appears here.

The maths

Human years

human age = 16 x ln(dog age in years) + 31

A natural logarithm, so a dog ages fastest early and more slowly later. Months are turned into a fraction of a year first, so 2 years 6 months is 2.5.

Where it stops

valid from 3 months to 30 years

The formula was fitted to dogs from about 2 months old, but a number for a very young puppy would suggest accuracy nobody has. The calculator stays silent under 3 months.

What it leaves out

It was fitted to Labrador Retrievers. A giant breed tends to age faster than a toy breed, and this formula does not know which yours is.
It compares how the body has aged, not how the dog behaves. A fit 12-year-old can act far younger than the number.
It says nothing about health, life expectancy or when to see a vet.

Sources

Wang T, Ma J, Hogan AN et al. Quantitative translation of dog-to-human aging by conserved remodeling of the DNA methylome. Cell Systems 11(2), 2020. Formula and the Labrador Retriever sample.

Questions

Older dogs often need shorter walks and gentler grooming, and a good local business will plan around that. Find a local groomer, walker or daycare.

More tools

All 11 calculators

Dog age in human years

Dog age

Human years

6 months

1 year

2 years

3 years

4 years

5 years

6 years

7 years

8 years

9 years

10 years

12 years

14 years

16 years

The maths

Human years

human age = 16 x ln(dog age in years) + 31

A natural logarithm, so a dog ages fastest early and more slowly later. Months are turned into a fraction of a year first, so 2 years 6 months is 2.5.

Where it stops

valid from 3 months to 30 years

The formula was fitted to dogs from about 2 months old, but a number for a very young puppy would suggest accuracy nobody has. The calculator stays silent under 3 months.

What it leaves out

It was fitted to Labrador Retrievers. A giant breed tends to age faster than a toy breed, and this formula does not know which yours is.

It compares how the body has aged, not how the dog behaves. A fit 12-year-old can act far younger than the number.

It says nothing about health, life expectancy or when to see a vet.

Sources

Wang T, Ma J, Hogan AN et al. Quantitative translation of dog-to-human aging by conserved remodeling of the DNA methylome. Cell Systems 11(2), 2020. Formula and the Labrador Retriever sample.