Dog years: The calculator

Big and little dog Image copyright Thinkstock

Working out your dog's true age used to be a case of simply multiplying it by seven. But it's more complicated than that, and here's a handy calculator to do it for you.

A recent Magazine feature explained that:

  • Different breeds of dog age at varying speeds
  • Dogs age at varying speeds at different stages of their lives

With that in mind, we've built a calculator for you to work out your dog's true age - its age in "dog years".

Alternatively, you can find out how old you would be if you were a dog. You can choose to be a labrador, a spaniel, a whippet, or any one of 20 breeds.

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Dog age calculator
  • My dog
  • My life as a dog
My dog's age...
My age is...
Choose a breed of dog

Age as a human


Previous age as a human


This breed's life expectancy


Source: BBC calculations on data from UK Kennel Club and US Veterinary Medical Database

The calculator uses these multipliers for the first two years of a dog's life:

  • 12.5 for small dogs
  • 10.5 for medium-sized dogs
  • 9 for large dogs

Then, for the third and subsequent years of the dog's life, each human year has to be multiplied by between 4.3 and 13.4 years, depending on the breed:

Small: Dachshund (Miniature) 4.32, Border Terrier 4.47, Lhasa Apso 4.49, Shih Tzu 4.78, Whippet Medium 5.30, Chihuahua 4.87, West Highland White Terrier 4.96, Beagle 5.20, Miniature Schnauzer 5.46, Spaniel (Cocker) 5.55, Cavalier King Charles 5.77, Pug 5.95, French Bulldog 7.65

Medium: Spaniel 5.46, Retriever (Labrador) 5.74, Golden Retriever 5.74, Staffordshire Bull Terrier 5.33, Bulldog 13.42

Large: German Shepherd 7.84, Boxer 8.90

The calculator does not work for cross breeds, sadly, but on average these live 1.22 years longer than pure breeds, according to Dan O'Neill (from Petts Wood in London...) who is researching the subject for a PhD at the Royal Veterinary College.

Nor does the calculator work for cats. What we can say is that the average life expectancy of a cat is 12.1 years, which equates to 64 human years.

Guidelines issued by the American Association of Feline Practitioners say that cats reach 10 human years in their first six months and are approximately 24 at the age of two years. After this their age increases by four "cat years" every year.

Here is a selection of longevity secrets of readers' pets who lived past 100 'dog years'.

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