Dog years to human years

Dog Age Calculator

Enter your dog's age and size to see their age in human years, their life stage, and what that means for care.

Quick answer

A 1-year-old dog is about 15 in human years, and a 2-year-old is about 24. After that, each dog year adds roughly 4 human years for small dogs and up to 7 for giant breeds, according to the AKC chart based on AVMA guidance. The "multiply by 7" rule is a myth.

Dog age chart: dog years to human years

Find your dog's age on the left and their adult size across the top. After you calculate, your dog's row is highlighted.

Human-year equivalents from the AKC chart (based on AVMA guidance).
Dog age	Small≤ 20 lb	Medium21–50 lb	Large51–100 lb	Giant100+ lb
1 year	15	15	15	12
2 years	24	24	24	22
3 years	28	28	28	31
4 years	32	32	32	38
5 years	36	36	36	45
6 years	40	42	45	49
7 years	44	47	50	56
8 years	48	51	55	64
9 years	52	56	61	71
10 years	56	60	66	79
11 years	60	65	72	86
12 years	64	69	77	93
13 years	68	74	82	100
14 years	72	78	88	107
15 years	76	83	93	114
16 years	80	87	99	121

How to calculate your dog's age in human years

The chart follows three simple steps from the American Veterinary Medical Association, published by the American Kennel Club:

First year: about 15 human years (12 for giant breeds, which mature more slowly).
Second year: about 9 more, so a 2-year-old dog is roughly 24.
Every year after: about 4 human years for small dogs, 4 to 5 for medium dogs, 5 to 6 for large dogs and 7 for giant breeds.

For ages between whole years, the calculator fills in the gap in a straight line, so a 5½-year-old large dog comes out at about 41. For dogs older than 16, it keeps adding the chart's last yearly step and marks the result as beyond the chart.

Why the "7 dog years" rule is wrong

The idea that one dog year equals seven human years is easy to remember, but it doesn't match how dogs grow. Most dogs are physically mature by their first birthday, which is closer to a human teenager than a 7-year-old child. After that, ageing slows down.

Size changes the picture too. A 15-year-old small dog is about 76 in human years on the AKC chart, while the ×7 rule would say 105. A 1-year-old of any size is about 15, not 7. The AVMA states plainly that dogs do not age at a rate of seven human years for each year.

The DNA formula: 16 × ln(age) + 31

In 2020, researchers at UC San Diego compared chemical changes to DNA (methylation) in 104 Labrador Retrievers with the same changes in people. They proposed this conversion:

human age = 16 × ln(dog age) + 31

By this measure, a 1-year-old dog is like a 31-year-old person and a 12-year-old Labrador is about 70. The curve shows how fast dogs age early on. It has limits: it was built from one breed, and the study authors note that other breeds may age differently. Because of the logarithm, it gives negative numbers for young puppies, so we only show it for dogs 1 year and older.

How size and breed change the way dogs age

Among mammals, bigger species usually live longer, but within dogs it's the opposite. US veterinary records from more than 13 million dogs show small purebreds have a life expectancy at birth of about 13.5 years, medium dogs 12.7, large dogs 11.5 and giant breeds 9.5. A study of 74 breeds found that large dogs die younger mainly because they age faster once adult.

Breed matters on top of size. See how long each breed usually lives in our dog lifespan by breed guide.

When is a dog considered a senior?

AAHA's 2019 guidelines define the senior stage as the last 25% of a dog's estimated lifespan. That means the start of the senior years depends on how long dogs of that size or breed usually live:

Life expectancy: Montoya et al. 2023 (US, Banfield). Senior start = 75% of life expectancy (AAHA 2019).
Size	Life expectancy	Senior from about
Small ≤ 20 lb	13.5 yrs	10.1 yrs
Medium 21–50 lb	12.7 yrs	9.5 yrs
Large 51–100 lb	11.5 yrs	8.6 yrs
Giant 100+ lb	9.5 yrs	7.1 yrs

The AVMA's advice for owners is more cautious: many vets suggest twice-yearly checkups from about age 7 for small dogs and 5 to 6 for large dogs. Either way, senior dogs benefit from earlier checkups, a lean body weight and attention to changes in mobility, appetite and behavior.

How old is my dog if I don't know their birthday?

Many rescue dogs come with an estimated age rather than a birth date. Shelters and vets judge age from teeth, eyes, coat and body condition. That works well for young puppies, whose teeth change on a predictable schedule, but for adult dogs it gives a range of a few years.

If your shelter gave you a range such as "about 1 to 2 years", choose Shelter range in the calculator. You'll see the human-age range and life stage for both ends, which is more honest than a single number.

Dog life stages explained

AAHA describes five life stages. They are based on development and health, not fixed birthdays:

Puppy: from birth until rapid growth stops, usually around 6 to 9 months depending on size.
Young adult: until physical and social maturity is complete, for most dogs by 3 to 4 years.
Mature adult: the prime years, until the last quarter of the expected lifespan.
Senior: the last 25% of the expected lifespan.
End of life: the final stage, which can come at any age.

The calculator shows the first four. End of life depends on health, not age, so we don't estimate it.

Frequently asked questions

Is 1 dog year really 7 human years?

No. Dogs mature much faster than people at the start of life and more slowly later. The AKC chart, based on AVMA guidance, puts a 1-year-old dog at about 15 human years and a 2-year-old at about 24. After that, each year adds roughly 4 to 7 human years, depending on size. The ×7 rule makes young dogs seem too young and small senior dogs seem too old.

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

About 56 for a small dog, 60 for a medium dog, 66 for a large dog and 79 for a giant breed, according to the AKC chart.

When is a dog considered a senior?

The American Animal Hospital Association (AAHA) defines the senior stage as the last 25% of a dog's expected lifespan. Using US life expectancy by size, that is around 10.1 years for small dogs, 9.5 for medium, 8.6 for large and 7.1 for giant dogs. The AVMA takes a more cautious view and suggests treating small dogs as seniors from about 7 and large dogs from 5 to 6.

Do small dogs live longer than large dogs?

On average, yes. In US veterinary records, small purebred dogs have a life expectancy of about 13.5 years at birth, compared with about 9.5 years for giant breeds. Research suggests large dogs die younger mainly because they age faster.

Is a 1-year-old dog still a puppy?

By AAHA's definition, puppyhood ends when rapid growth stops, usually around 6 to 9 months depending on size, so most 1-year-olds are young adults. Large and giant breeds can keep filling out for longer, so feed them for their size and stage.

What is the most accurate dog age formula?

There is no single exact formula. The AKC chart accounts for size, which matters a lot. The UC San Diego formula (16 × ln(age) + 31) is based on DNA changes, but it was built from 104 Labrador Retrievers only. We use the AKC chart for your result and show the DNA formula as a second opinion.

Why does the DNA formula give strange results for puppies?

It uses a natural logarithm, which falls steeply toward zero. For a 1-month-old puppy it gives about −8.8 human years, which makes no sense. That is why we only show it for dogs aged 1 year and older.

How can I tell how old my rescue dog is?

Start with the shelter's estimate and ask your vet, who can narrow it down from teeth, eyes, coat and overall condition. Any estimate for an adult dog is a range, so use the Shelter range option above to see the human-age range and life stage for both ends.

Keep going

Dog Lifespan by BreedHow long each breed usually lives, with study data

Last reviewed Sep 30, 2026 · How we calculate

Sources

Estimates only — not a substitute for veterinary advice. Read our disclaimer.