If you adopted a dog with no paperwork, you may not know its age. You can still make a good estimate. Vets do it every day, mostly by looking at a few things.
Key facts
- Teeth are the single best age clue in a younger dog; the full adult set is in by about seven months.
- Tartar build-up and dulling on the back teeth indicate a middle-aged dog; heavy tartar and worn or missing teeth indicate a senior.
- Grey hairs around the muzzle usually start in middle age, and slight eye cloudiness is common in older dogs.
- Weighing all clues together, a vet can usually estimate a dog’s age within a year or two.
Teeth tell the most
Teeth are the single best clue in a younger dog.
- Puppies have small, white, needle-sharp baby teeth, with the full adult set in by about seven months.
- Young adults have clean, white adult teeth.
- Middle-aged dogs show some tartar build-up and dulling, especially on the back teeth.
- Senior dogs often have heavy tartar, worn surfaces, and sometimes missing teeth.
Teeth are less reliable in older dogs, because dental care and chewing habits vary so much.
Other clues
- Muzzle: grey hairs around the muzzle and face usually start in middle age.
- Eyes: a slight cloudiness is common in older dogs.
- Coat: it may thin or coarsen with age.
- Energy and movement: younger dogs bounce; older dogs are stiffer getting up, slower on stairs.
None of these is exact. A vet weighing all of them together can usually estimate within a year or two. For context on where that estimate sits, see our guide to the average dog lifespan by size class.
Once you have an estimate
A vet’s estimate gives you a number in dog years. To understand what that means for your dog’s life stage, put it into the dog age calculator with your dog’s breed or size. A “5-year-old” rescue is a young adult if it is small, and approaching senior if it is a giant breed. From there, the evidence-based steps for extending your dog’s lifespan apply at any starting age.
