Nobody knows where the seven dog years to one human year theory came from or at least no-one is claiming responsibility for it. It first appeared in maths text books in the 1960s and questions were set asking children to calculate the age of a dog using the 7:1 ratio.
For the dog species as a whole it’s not a bad estimate at all.
If you factor in the varying rates of ageing in early part of a dog’s life and the differing life expectancies a more accurate estimate across all breeds would be six dogs years to one human year.
However if you look at opposing ends of the spectrum a Bulldog will age an average of 13 years per human year whereas for a Miniature Dachshund it’s just over four years.
And Meg, my Westie? She was not 135 but 109 when she passed away, the calculator suggests – ancient in human terms, but not unheard of. I think she’d have settled for that.
