How to Tell How Old a Dog Is: Teeth, Eyes and Coat Clues

A puppy's teeth tell its age to within a few weeks, because baby and adult teeth come in on a predictable schedule that finishes at about 7 months. After that, every clue gives you a range. Tartar, tooth wear, a hazy lens, a gray muzzle and a bonier spine all point somewhere, and even a veterinarian's best answer for an adult dog is a range of years, not a birthday.

That range is still useful. It tells you whether you have a young adult, a dog in the middle years or a senior, and that life stage is what changes food, exercise and how often your dog should see the vet. Work through the clues below in order, teeth first.

Want your dog's age in human years? See the dog age chart.

Start with the teeth

Teeth are the best place to start with a dog of unknown age, and for puppies they are the most reliable clue you have. Dogs have 28 baby (deciduous) teeth and 42 adult teeth, so counting what is in the mouth already narrows things down. Our guide to dental formulas in animals shows where each tooth sits.

Puppies: the tooth timeline

The U.S. Department of Agriculture's Aging Puppies by Teeth guide lays out the typical schedule:

Source: USDA APHIS, Aging Puppies by Teeth (2023). Individual puppies vary.

The Merck Veterinary Manual gives a slightly different version of the same story: baby teeth start erupting at 3 to 5 weeks, adult teeth start appearing at around 4 to 5 months, and all permanent teeth are in by 7 months. So "about 7 months" for a full adult set is a fair rule, with some dogs finishing closer to 8. Even in young dogs, Merck calls tooth-based aging "only somewhat accurate", so treat the table as a guide to within a few weeks.

Two quick rules from the USDA guide:

• Fewer than 28 baby teeth and no adult teeth: the puppy is likely under 8 weeks old.
• Baby premolars still present and only the first bottom molars in: the puppy is likely under 6 months old.

Very young puppies give you one more clue. Most open their eyes between 7 and 14 days after birth, according to VCA Animal Hospitals, so a pup with sealed eyelids is under about two weeks old. A puppy whose eyes are still closed at 14 days should be seen by a vet.

If your puppy is somewhere in the 3 to 7 month window, expect chewing. Our puppy teething survival guide covers what is normal.

Adult dogs: wear and tartar give a range

Once all 42 adult teeth are in, the schedule stops being useful. From then on, vets look at wear on the tips of the teeth, tartar (calculus, which is plaque hardened by minerals in saliva), staining and gum health. Merck notes that vets can estimate an adult's age from these wear patterns, and that small and toy breeds are harder to age this way. Expect an estimate.

This rough guide comes from Animal Dental Specialists, a veterinary dental practice. Treat each band as a starting point:

Source: Animal Dental Specialists. A rough guide, not a veterinary standard.

Sources disagree at the edges. The adoption charity Michelson Found Animals, for example, puts the first tartar at around 4 years rather than 1 to 2. That disagreement is the honest picture: adult tooth age is a range.

In the photo above, notice the thick brown tartar on the canines and back teeth, the gum line pulled back from the roots, and the gaps where teeth are missing. That mouth reads "older dog", but in a small breed with no dental care it can show up earlier than in a large dog.

Why teeth can fool you

Tartar measures dental care and genetics as much as age. Three things skew the reading:

• Size and breed. The AAHA Dental Care Guidelines warn that dogs under about 20 to 25 pounds at maturity usually need more dental care, and flat-faced breeds have more dental problems because their teeth are crowded. A UK study of over 22,000 dogs found the odds of periodontal disease fell steadily as adult body weight went up. A 3-year-old toy breed can have the mouth of a much older retriever.
• Retained baby teeth. Sometimes a baby tooth, most often a canine, stays put when the adult tooth comes in. The crowding traps food, so tartar and gum inflammation build up fast. A young dog with "extra" teeth and early tartar can look older than it is.
• Diet, chewing and care. Chewing habits, diet and any past brushing or professional cleanings all change how worn and tartared the teeth look.

Check the eyes

Many dogs develop a bluish-gray haze in the center of the eye as they age. This is nuclear (or lenticular) sclerosis: the lens slowly gets denser through life. VCA describes it in middle-aged to senior dogs and lists it, with cataracts, among the most common eye problems in dogs over 9. Vision is not significantly affected in most dogs.

A cataract is a different thing, and it matters because it can reduce vision:

You can't tell them apart for sure at home. The Cornell University Veterinary Specialists ophthalmology team says an eye exam is needed, and other problems such as corneal disease, glaucoma and inflammation can also make an eye look cloudy. See your vet promptly if a cloudy eye comes with squinting, redness, discharge, pawing or rubbing at the eye, or any sign your dog is not seeing well.

Look at the coat

Gray hair is a real but loose clue. PetMD's veterinarians note that age-related graying is usually most noticeable on the muzzle, around the eyes and on the paws. A dog gray on the chest, face, legs, ears and paws may be nearing senior status, according to the adoption charity Michelson Found Animals.

Two cautions before you read age into a gray face:

• Some young dogs go gray early. A study of about 400 dogs aged 1 to 4 found that dogs their owners rated as more anxious or impulsive tended to have grayer muzzles. That is a link, not proof of cause, but it means a gray chin on its own does not make a dog old.
• Some dogs are born with white faces. White markings from birth say nothing about age.

Feel the body: muscle and joints

Run your hands along your dog's back and hips. In older dogs the muscles along the spine shrink, so the backbone feels more prominent. This age-related loss of muscle is called sarcopenia. The AAHA Senior Care Guidelines note that dogs tend to lose lean muscle and gain fat as seniors, then lose weight overall as they get very old.

Movement is the other half. Stiffness after rest, slower stairs and reluctance to jump often come from osteoarthritis, which AAHA lists among the issues a senior visit should address. Hearing can fade with age too, so a dog that no longer hears you come home may be older, or may simply need its ears checked.

None of these signs are age-specific on their own. A young dog with an old injury can be stiff, and a fit senior can have good muscle. Use them to back up what the teeth and eyes suggest.

What your vet adds

A vet visit is the best way to firm up the estimate, and a newly adopted dog needs one anyway. Expect:

• A full physical exam. Your vet looks at the teeth and gums, eyes, coat and body condition, and feels the limbs, joints and spine.
• Dental X-rays in young dogs. As a tooth ages, its pulp cavity (the soft center) narrows. A 2022 study found that measuring the pulp width of the canine teeth on X-rays can sort dogs into age groups, most accurately in dogs up to about 15 months old.
• Bloodwork as a health check, not an age test. Lab work does not give a birth date. It tells your vet how the organs are doing, which matters most if the clues point to an older dog.

Even with all of that, the answer is a range. PetMD's vets call any estimate after 7 months "more subjective." A good vet will tell you the range and why.

Put the clues together: your dog's life stage

The most useful result is a life stage, because that is what your vet uses to plan care. The AAHA Canine Life Stage Guidelines use four:

AAHA sets no fixed senior age; it depends on how long your dog is expected to live. As an example, a dog expected to live about 12 years becomes a senior at around 9. If the clues land your dog in the senior row, our guide on how to take care of a senior dog is a good next read.

Pick a working birthday in the middle of your range and write it down. It gives your vet records a reference point, and you can adjust it if new clues turn up.

When to ask your vet

Book a visit soon after adoption, and sooner if you see any of these:

• A cloudy eye with squinting, redness, discharge, rubbing or signs of poor vision.
• Baby teeth still in place next to adult teeth, or a puppy over about 8 months without a full adult set.
• Heavy tartar, red or receding gums, or loose, broken or missing teeth.
• Stiffness, limping, trouble with stairs or jumping, or muscle loss along the back.
• A puppy whose eyes have not opened by 14 days.

Quick answers

Can a vet tell exactly how old my dog is? For puppies, close to it, from the teeth. For adults, no: your vet gives an estimated range from the exam, and X-rays narrow it mainly in young dogs.

At what age does a dog have all its adult teeth? At about 7 months, per Merck. The USDA guide says 7 or 8 months.

Does a gray muzzle mean my dog is old? Not on its own. Some dogs gray early, some are born with white faces. Graying that spreads to the body and paws is a better sign of age.

My dog's eyes look blue and cloudy. Is it a cataract? Often it is nuclear sclerosis, a normal aging change that usually leaves vision intact. Only an eye exam can tell, so mention it to your vet, and go promptly if the eye looks sore or your dog is bumping into things.

Originally written by Helen Roberts. Updated by the I Love Veterinary editorial team.

Sources

• USDA APHIS Animal Care: Aging Puppies by Teeth (APHIS-23-030, 2023)
• Merck Veterinary Manual: Dental Development of Dogs
• AAHA: 2019 Dental Care Guidelines for Dogs and Cats
• O'Neill et al., Journal of Small Animal Practice (2021): Epidemiology of periodontal disease in dogs in the UK primary-care veterinary setting
• Animal Dental Specialists: Dogs Teeth and Age
• Michelson Found Animals: How Old Is My Adopted Dog?
• VCA Animal Hospitals: Raising Puppies
• VCA Animal Hospitals: Lenticular Sclerosis in Dogs
• Cornell University Veterinary Specialists: Age Related Ocular Cloudiness in Dogs
• King et al., Applied Animal Behaviour Science (2016): Anxiety and impulsivity, factors associated with premature graying in young dogs
• PetMD: How Old Is My Dog? How to Determine a Dog's Age
• AAHA: 2023 Senior Care Guidelines for Dogs and Cats
• AAHA: Canine Life Stage Definitions (2019)
• Van den Broeck et al., Anatomia, Histologia, Embryologia (2022): Age estimation in young dogs by radiographic assessment of the canine pulp cavity/tooth width ratio

This article is for general information and is not a substitute for advice from your veterinarian.