DogYearsFrequently asked questions
The questions people actually ask about dog years — including the ones where the honest answer is “it depends” or “unknown”.
Questions
Is the 7-year rule ever right?
Only by coincidence in a narrow middle band. For a medium dog around age 4–6 the two answers pass near each other; for puppies, old dogs and giant breeds the rule is off by years in both directions. A 1-year-old dog is about 15 in human terms, not 7; a 15-year-old giant-breed dog is about 116 on the size chart, not 105.
Which number should I quote for my dog?
Quote the size chart for everyday conversation — it reflects size, which is the biggest real-world factor. If someone asks about the DNA research, quote the formula result as well and enjoy explaining why they differ.
Does neutering or diet change the conversion?
They can change actual lifespan and healthspan, but the conversion charts are population averages that do not adjust for individual factors. There is no validated 'subtract a year if neutered' adjustment, so we do not invent one.
How accurate is the epigenetic formula for small dogs?
Unknown — and we label it that way. It was fitted on Labrador Retrievers only. Applying it to a Chihuahua is an extrapolation the original study does not directly support, which is exactly why the calculator leads with the size chart.
What about mixed-breed dogs?
Use their adult weight to choose the size band. If your dog sits between bands, both columns are honest answers and the truth is presumably in between.
Can I use this for other animals?
Only cats have their own page here, because their curve is documented separately. We do not extrapolate these formulas to rabbits, horses or anything else — each species ages on its own pattern.
Is my data stored when I use the calculator?
No. Everything runs in your browser; there is no account, no upload and nothing to store. See the privacy page for the plain version.