u/IllSignature4490

the multiply by 7 rule for pet ages has been bothering me for a while

now. apparently its just made up from the 1950s with no actual biology

behind it, just someone doing rough math like "dogs live 10 years,

humans live 70, so 1 dog year = 7 human years" and thats it. but a 1

year old labrador is already sexually mature and basically full grown

which is way closer to a 15 year old human than a 7 year old kid. a 7

year old great dane is already geriatric while a 7 year old chihuahua

is still middle aged so size of the dog matters a lot.

so i ended up building a free calculator that uses the actual size

adjusted formula vets and the akc use, plus the 2019 ucsd epigenetic

clock research (wang et al). its here if anyone wants to try it on

their pet:

https://realpetage.com

works for both dogs and cats. you can pick a specific breed (about

50 of em in there) or just enter weight, since body size is the

biggest predictor of how fast a dog ages. also has life stage

classification (puppy to geriatric), share card with your pets

photo, that kind of thing. no signup, no ads (yet lol), runs

entirely in your browser.

genuinely curious to hear feedback, especially on the calculator

ux and the breed data. and if your vet has ever told you your pet

is older or younger than the x7 rule suggests, would love to hear

that too. feels like most large breed owners are underestimating

their pets age by years.

ok so the multiply by 7 rule for pet ages has been bothering me for

a while now. apparently its just made up from the 1950s with no

actual biology behind it, just someone doing rough math like "dogs

live 10 years, humans live 70, so 1 dog year = 7 human years" and

thats it. but if you think about it a 1 year old labrador is already

sexually mature and basically full grown which is way closer to a 15

year old human than a 7 year old kid. a 7 year old great dane is

already geriatric while a 7 year old chihuahua is still middle aged

so the math really depends on the size of the dog which most calcs

dont take into account.

apparently the akc actually uses a different formula that factors in

weight. small dogs (under 20 lbs) age about 4 human years per dog

year after age 2, medium dogs around 5, large dogs around 6, and

giant breeds around 7. theres also a 2019 ucsd study (the wang et al

paper if anyones nerdy enough to look it up) that mapped dna

methylation patterns to figure out a more accurate aging curve.

cats are similar but body size matters way less for them, indoor

lifestyle matters way more. indoor cats average 15 to 17 years,

outdoor cats average like 2 to 5 because of cars and predators.

genuinely curious tho, has your vet ever told you your pet is

"older" or "younger" than what the x7 rule says? feels like most

large breed owners are underestimating their pets age by years and

small breed owners are overestimating, but i could be wrong.