Dog Age Calculator

Convert dog years to human years the way vets actually do it — adjusted for your dog's size. Pick your breed and the size class is set for you.

Last reviewed July 2026 · Free · Nothing you enter is stored

Dog's age (years) i

Breed i

Size class i

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Educational estimate. Individual dogs age differently based on genetics, weight, and health — your vet is the best guide to your dog's life stage.

Why "multiply by seven" was always wrong

The seven-year rule appears to have started as a marketing simplification in the 1950s, built on the rough observation that people lived about 70 years and dogs about 10. It fails in both directions. A one-year-old dog is not a seven-year-old child — it is sexually mature, physically adult, and closer to a human teenager. And a 13-year-old Chihuahua is not the same age as a 13-year-old Great Dane; one is an elderly but functional senior, the other has usually already died.

Two corrections fix most of the error. The first is front-loading: puppies compress an enormous amount of development into twelve months, so year one is worth roughly 15 human years and year two adds about 9 more. The second is size: after maturity, bigger dogs burn through the remaining years faster.

How much faster do big dogs age?

Every year after a dog's second birthday is worth a different number of human years depending on its adult weight. This is the table this calculator applies:

Size class	Adult weight	Human years per dog year (after age 2)	Typical examples
Toy	under 12 lbs	4	Chihuahua, Pomeranian, Yorkshire Terrier
Small	12–20 lbs	4	Beagle, French Bulldog, Miniature Schnauzer
Medium	20–50 lbs	5	Border Collie, Australian Shepherd, Bulldog
Large	50–90 lbs	5.5	Labrador Retriever, German Shepherd, Boxer
Giant	90+ lbs	6.5	Great Dane, Mastiff, Saint Bernard

The consequence compounds. At age 10, a toy breed is around 56 in human terms and a giant breed is around 76 — a twenty-year gap opened up by nothing but body mass. It is also why "senior" arrives at different times: giant breeds are typically considered senior at six, large breeds at seven, medium at eight, and small and toy breeds not until ten.

The epigenetic clock, and why we show both numbers

In 2020 a team at UC San Diego compared DNA methylation — chemical tags that accumulate on DNA in a clock-like way — across 104 Labrador Retrievers and 320 humans. The resulting formula, human age = 16 × ln(dog age) + 31, is logarithmic rather than linear, which matches biology far better: a dog's first months really are worth several human years each, and the curve flattens with time.

Its limitation is the sample. Every dog in the study was a Labrador, a large breed, so the formula has no way of knowing that a Chihuahua's remaining years pass more slowly. For a Labrador the two methods land close together. For a Yorkshire Terrier the epigenetic figure runs high, and for a Mastiff it runs low. Showing both gives you the range, and the truth for your dog sits somewhere inside it.

Life expectancy by breed

Aging rate and lifespan are related but not the same thing. These are the longest- and shortest-lived breeds in our reference data:

Longest-lived

Coton de Tulear — 15–19 years
Lagotto Romagnolo — 15–17 years
Manchester Terrier — 15–17 years
Chinese Crested — 13–18 years
Tibetan Terrier — 15–16 years
Xoloitzcuintli — 13–18 years

Shortest-lived

Dogue de Bordeaux — 5–8 years
Irish Wolfhound — 6–8 years
Neapolitan Mastiff — 7–9 years
Mastiff — 6–10 years
Leonberger — 7–9 years
Bullmastiff — 7–9 years

The single biggest thing an owner controls is body condition. A fourteen-year Purina study following Labrador littermates found that dogs kept at a lean body condition lived a median of 1.8 years longer than their moderately overweight siblings — more than any supplement, diet trend, or breed choice will ever buy you. Our dog food calculator works out the portion that keeps a dog there.

Full breed reference

Adult weight, size class, and typical life expectancy for all 146 breeds in our data. Choose any of them in the dropdown above to apply the matching aging rate.

Breed	Size class	Adult weight (lbs)	Life expectancy (yrs)
Australian Terrier	toy	15–20	11–15
Brussels Griffon	toy	8–12	12–15
Chihuahua	toy	3–6	14–16
Chinese Crested	toy	8–12	13–18
Chiweenie	toy	5–12	12–16
Havanese	toy	7–13	14–16
Italian Greyhound	toy	7–14	14–15
Maltese	toy	4–7	12–15
Maltipoo	toy	5–20	12–16
Miniature Pinscher	toy	8–11	12–16
Morkie	toy	4–8	10–13
Papillon	toy	5–10	14–16
Pekingese	toy	7–14	12–14
Pomeranian	toy	3–7	12–16
Poodle (Toy)	toy	4–6	10–18
Shih Tzu	toy	9–16	10–18
Shorkie	toy	5–15	11–16
Silky Terrier	toy	8–11	13–15
Toy Fox Terrier	toy	4–9	13–15
Yorkipoo	toy	4–15	12–15
Yorkshire Terrier	toy	4–7	11–15
American Eskimo Dog	small	6–35	13–15
Basenji	small	22–24	13–14
Beagle	small	20–30	10–15
Bedlington Terrier	small	17–23	11–16
Bichon Frise	small	12–18	14–15
Border Terrier	small	11–16	12–15
Boston Terrier	small	12–25	11–13
Cairn Terrier	small	13–14	13–15
Cardigan Welsh Corgi	small	25–38	12–15
Cavalier King Charles Spaniel	small	13–18	12–15
Cavapoo	small	9–25	12–15
Cockapoo	small	12–25	13–16
Coton de Tulear	small	8–15	15–19
Dachshund	small	16–32	12–16
French Bulldog	small	16–28	10–12
Jack Russell Terrier	small	9–15	13–16
Lhasa Apso	small	12–18	12–15
Manchester Terrier	small	12–22	15–17
Miniature American Shepherd	small	20–40	12–13
Miniature Schnauzer	small	11–20	12–15
Norfolk Terrier	small	11–12	12–16
Norwich Terrier	small	11–12	12–15
Pembroke Welsh Corgi	small	24–30	12–13
Pomsky	small	20–38	12–15
Poodle (Miniature)	small	10–15	10–18
Pug	small	14–18	13–15
Puggle	small	15–40	10–15
Rat Terrier	small	10–25	12–18
Schipperke	small	10–16	13–15
Schnoodle	small	10–40	12–16
Scottish Terrier	small	18–22	12–15
Shetland Sheepdog	small	15–25	12–14
Shiba Inu	small	17–23	13–16
Smooth Fox Terrier	small	15–19	12–15
Welsh Terrier	small	20–22	12–15
West Highland White Terrier	small	15–20	13–15
Wire Fox Terrier	small	15–18	12–15
American Pit Bull Terrier	medium	30–65	12–16
American Staffordshire Terrier	medium	40–70	12–16
Aussiedoodle	medium	25–70	10–13
Australian Cattle Dog	medium	35–50	12–16
Australian Shepherd	medium	40–65	12–15
Basset Hound	medium	40–65	12–13
Border Collie	medium	30–55	12–15
Brittany	medium	30–40	12–14
Bull Terrier	medium	50–70	12–13
Bulldog	medium	40–50	8–10
Chinese Shar-Pei	medium	45–60	8–12
Cocker Spaniel	medium	20–30	10–14
English Springer Spaniel	medium	40–50	12–14
Keeshond	medium	35–45	12–15
Lagotto Romagnolo	medium	24–35	15–17
Norwegian Elkhound	medium	48–55	12–15
Nova Scotia Duck Tolling Retriever	medium	35–50	12–14
Pharaoh Hound	medium	45–55	12–14
Poodle (Standard)	medium	40–70	10–18
Portuguese Water Dog	medium	35–60	11–13
Samoyed	medium	35–65	12–14
Siberian Husky	medium	35–60	12–14
Soft Coated Wheaten Terrier	medium	30–40	12–14
Staffordshire Bull Terrier	medium	24–38	12–14
Standard Schnauzer	medium	30–50	13–16
Tibetan Terrier	medium	18–30	15–16
Whippet	medium	25–40	12–15
Xoloitzcuintli	medium	15–55	13–18
Afghan Hound	large	50–60	12–18
Airedale Terrier	large	50–70	11–14
Akita	large	70–130	10–13
Alaskan Malamute	large	75–85	10–14
American Foxhound	large	60–70	11–13
Belgian Malinois	large	40–80	14–16
Bernedoodle	large	50–90	12–15
Black and Tan Coonhound	large	65–110	10–12
Bloodhound	large	80–110	10–12
Bluetick Coonhound	large	45–80	11–12
Borzoi	large	60–105	9–14
Boxer	large	55–80	10–12
Chesapeake Bay Retriever	large	55–80	10–13
Collie	large	50–75	12–14
Dalmatian	large	45–70	11–13
Doberman Pinscher	large	60–100	10–12
English Foxhound	large	60–75	10–13
English Setter	large	45–80	11–13
German Shepherd	large	50–90	9–13
German Shorthaired Pointer	large	45–70	10–12
German Wirehaired Pointer	large	50–70	12–14
Giant Schnauzer	large	55–85	12–15
Golden Retriever	large	55–75	10–12
Goldendoodle	large	50–90	10–15
Gordon Setter	large	45–80	10–12
Greyhound	large	60–70	10–13
Ibizan Hound	large	45–50	11–14
Irish Setter	large	60–70	12–15
Labradoodle	large	50–65	12–14
Labrador Retriever	large	55–80	11–13
Old English Sheepdog	large	60–100	10–12
Otterhound	large	80–115	10–13
Plott Hound	large	40–60	12–14
Pointer	large	45–75	12–17
Redbone Coonhound	large	45–70	12–15
Rhodesian Ridgeback	large	70–85	10–12
Rottweiler	large	80–135	9–10
Saluki	large	40–65	10–17
Sheepadoodle	large	60–90	12–15
Treeing Walker Coonhound	large	50–70	12–13
Vizsla	large	44–60	12–14
Weimaraner	large	55–90	10–13
Anatolian Shepherd Dog	giant	80–150	11–13
Bernese Mountain Dog	giant	70–115	7–10
Boerboel	giant	150–200	9–11
Bullmastiff	giant	100–130	7–9
Cane Corso	giant	88–120	9–12
Dogue de Bordeaux	giant	99–110	5–8
Great Dane	giant	110–175	7–10
Great Pyrenees	giant	85–160	10–12
Irish Wolfhound	giant	105–120	6–8
Komondor	giant	80–100	10–12
Kuvasz	giant	70–115	10–12
Leonberger	giant	90–170	7–9
Mastiff	giant	120–230	6–10
Neapolitan Mastiff	giant	110–150	7–9
Newfoundland	giant	100–150	9–10
Scottish Deerhound	giant	75–110	8–11
St. Bernard	giant	120–180	8–10
Tibetan Mastiff	giant	70–150	10–12

Breed weight and lifespan ranges follow AKC breed standards and established veterinary references. Individual dogs vary well outside these ranges.

Frequently asked questions

How do you calculate a dog's age in human years?

Not by multiplying by seven — that myth is long debunked. The veterinary convention counts the first year as about 15 human years, the second as 9 more (so a two-year-old dog is roughly 24), then adds 4 to 6.5 human years per year after that depending on the dog's size. Larger dogs age faster in the later years, which is why this calculator asks for a size class or breed rather than treating every dog the same.

What is the UCSD dog age formula?

A 2020 study at UC San Diego derived human_age = 16 × ln(dog_age) + 31 from DNA methylation patterns — chemical marks that accumulate on DNA at a predictable rate in both dogs and humans. It captures the very fast biological aging of puppyhood far better than the linear conventions do. Because the study drew on Labrador Retrievers, though, it over- and under-estimates at the extremes of size. We show it alongside the size-based convention so you can see both.

Do big dogs really age faster?

Yes, and the effect is dramatic. A Great Dane is geriatric by six or seven; many small terriers are still spry at fourteen. The leading explanation is that large breeds grow much faster as puppies, and that accelerated cell division carries a cost in accumulated damage and cancer risk later. That is why the per-year human equivalent after age two rises from about 4 years for toy breeds to 6.5 for giants.

Why does the breed dropdown change my answer?

Choosing a breed sets the size class for you and pulls in that breed's published life expectancy. It does not use a separate formula. Under the hood a Labrador and a Rottweiler get the same math, because they are both large breeds — the breed list exists to save you from guessing which weight class your dog falls into, and to show the lifespan range alongside the conversion.

How old is a dog in human years at 1, 7, and 10?

For a medium-sized dog: one year is about 15 human years, seven years is about 49, and ten years is about 64. For a giant breed the same ages come out at roughly 15, 56 and 76. The gap widens every year — that is the whole point of adjusting for size.

Does neutering, diet, or being a mixed breed change this?

Body condition matters more than any of them. Lean dogs live measurably longer than overweight ones — a landmark Purina lifespan study found about two extra years for dogs kept at ideal weight. Mixed breeds tend to sit near the average for their size class and often slightly outlive purebreds of the same weight. Use the size class that matches your dog's adult weight and the estimate will hold up.