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Dog & Cat Age Calculator

Enter your pet's age or birthday to see how old they are in human years. Dogs are converted by size (small to giant), and you can switch between the US AKC chart and Japan's Ministry of the Environment guideline, compare with the UCSD epigenetic clock, and see life stage tips and upcoming milestones.

Last updated: 2026/10/16 Calculator Feedback & bug reports

Your pet

Species
Dog size (adult weight)

e.g. Chihuahua, Toy Poodle, Miniature Dachshund, Pomeranian

Weight classes follow the AKC chart (20, 50 and 100 lb). For mixed breeds, choose by adult weight.

How to enter the age

Conversion standard

Dogs use the AKC (American Kennel Club) chart by weight; cats use the FelineVMA (formerly AAFP) chart.

Result

Enter an age or birthday to see the result here.

Pet age to human years chart (1–20 years)

Pet age to human years chart (US, AKC / FelineVMA)
Age Small dog Medium dog Large dog Giant dog Cat UCSD (dog)
1 15 15 15 12 15 31
2 24 24 24 22 24 42
3 28 28 28 31 28 49
4 32 32 32 38 32 53
5 36 36 36 45 36 57
6 40 42 45 49 40 60
7 44 47 50 56 44 62
8 48 51 55 64 48 64
9 52 56 61 71 52 66
10 56 60 66 79 56 68
11 60 65 72 86 60 69
12 64 69 77 93 64 71
13 68 74 82 100 68 72
14 72 78 88 107 72 73
15 76 83 93 114 76 74
16 80 87 99 121 80 75
17 84* 92* 105* 128* 84 76*
18 88* 96* 110* 135* 88 77*
19 92* 101* 116* 142* 92 78*
20 96* 105* 121* 149* 96 79*
  • Dogs: the AKC chart by weight. Cats: the FelineVMA (formerly AAFP) chart. Dog values marked * (17+ years) are estimates: the AKC chart stops at 16, so they extend it by the average yearly increase from 12 to 16 (small 4, medium 4.5, large 5.5, giant 7 per year).
  • The UCSD formula (16 × ln(age) + 31) is a reference value from a study of mostly Labrador Retrievers and has no size classes. * = beyond the study's data (0–16 years).
  • Kittens under 1 (FelineVMA): 1 month ≈ 1 year, 3 months ≈ 4 years, 6 months ≈ 10 years.

Methods & sources

The conversion methods used here and the sources for the life stage and care guidance (checked October 2026).

  1. Japan Ministry of the Environment, "Pet Food Guideline for Owners: Protecting the Health of Dogs and Cats" (飼い主のためのペットフード・ガイドライン, August 2018), p. 9: life stages (growth, adult, middle/old age) and dog/cat age equivalents (small–medium dogs and cats: 24 + (age − 2) × 4; large dogs: 12 + (age − 1) × 7). The growth period of giant dogs (about 2 years) is from the October 2009 edition. www.env.go.jp/nature/dobutsu/aigo/2_data/pamph/petfood_guide_1808.html
  2. Japan Ministry of the Environment, pamphlet "捨てず 増やさず 飼うなら一生" ("Don't abandon, don't overbreed — a pet is for life"; 2nd ed., March 2015), p. 7: dog and cat age table (1–17 years) and changes in later life, including nursing care. www.env.go.jp/nature/dobutsu/aigo/2_data/pamph/h2509a.html
  3. American Kennel Club (AKC), "How to Calculate Dog Years to Human Years" (updated September 14, 2026): chart "How old is my dog in human years?" by weight (ages 1–16) and the AVMA rule of thumb (15 for year one, +9 for year two, then about 5 per year). www.akc.org/expert-advice/health/how-to-calculate-dog-years-to-human-years/
  4. American Veterinary Medical Association (AVMA), "Caring for senior cats and dogs": senior ages by dog size, cats senior after 10, veterinary visits twice a year or more for seniors, and "dogs do not age at a rate of 7 human years per dog year". www.avma.org/resources-tools/pet-owners/petcare/senior-pets
  5. Feline Veterinary Medical Association (FelineVMA, formerly AAFP), "Feline Life Stages" (2026) and the 2021 AAHA/AAFP Feline Life Stage Guidelines: cat age equivalents (1 month ≈ 1 year up to 25 years ≈ 116), life stages and checkup frequency. catvets.com/life-stage
  6. Creevy KE, et al. 2019 AAHA Canine Life Stage Guidelines. J Am Anim Hosp Assoc. 2019;55(6):267–290: canine life stages and visit frequency. doi.org/10.5326/JAAHA-MS-6999
  7. Wang T, et al. Quantitative Translation of Dog-to-Human Aging by Conserved Remodeling of the DNA Methylome. Cell Systems. 2020;11(2):176–185.e6: epigenetic clock, human age = 16 ln(dog age) + 31. doi.org/10.1016/j.cels.2020.06.006
  8. Kraus C, Pavard S, Promislow DEL. The size–life span trade-off decomposed: why large dogs die young. The American Naturalist. 2013;181(4):492–505. doi.org/10.1086/669665

Values for dogs under 1 and AKC values for ages 17+ are extended by this tool from the published figures. The "super senior" stage (about 75+ in human years) is this tool's own guide.

Human-year equivalents and life stages are general guides and vary with breed, build and health. They are not a substitute for veterinary advice — if anything concerns you, please talk to your veterinarian.

Everything is calculated in your browser. The age or birthday you enter is never sent or stored.

How to Use

1

Choose dog or cat (and dog size)

Select "Dog" or "Cat". For dogs, pick the class that matches the adult weight: small (up to 20 lb / 9 kg), medium (21–50 lb), large (51–100 lb) or giant (over 100 lb / 45 kg).

2

Enter the age or birthday

Type the age in years and months, or switch to "Enter birthday" and pick the date of birth. With a birthday, today's age is worked out for you, along with a countdown to the next birthday.

3

Check human years and tips

See the age in human years, the current life stage with checkup guidance, how other methods compare, and when your pet will reach milestones like 40 or 60 in human years. Switch between the US (AKC) and Japan (MOE) standards and copy the result to share.

About the Dog & Cat Age Calculator

A free calculator that answers "how old is my pet in human years?". Because dogs age at different rates depending on size, it uses four weight classes — small, medium, large and giant. You can switch between the US AKC chart and the Japanese Ministry of the Environment guideline, and compare both with the epigenetic clock derived from DNA changes (the UCSD formula). The unfounded "one year equals seven" rule is not used.

For a person's age, use the Age Calculator; to count the days since your pet's adoption day, try the Anniversary Calculator; and for a live countdown to the next birthday, use the Countdown Timer.

Features

  • Four dog sizes plus catsSmall, medium, large and giant dogs as well as cats. Puppies and kittens under 1 are converted by months.
  • US and Japanese standards comparedSwitch between the AKC chart and Japan's MOE guideline, see the UCSD epigenetic clock side by side, and learn why the "×7" rule is a myth.
  • Life stage and care guidanceFrom puppy or kitten to senior, see the current stage and checkup frequency guidance with sources.
  • Milestones and birthday countdownFind out when your pet turns 20, 40, 60 and more in human years, plus the days until the next birthday.

Use Cases

  • Finding out how old your dog or cat is in human years
  • Deciding when to think about senior food and more frequent checkups
  • Celebrating a milestone like "60 in human years" with the family
  • Estimating the human-year age of an adopted rescue pet
  • Comparing how small and large dogs, or dogs and cats, age

FAQ

Is "one dog year equals seven human years" true?
No. Dogs grow up very fast in their first year or two — by about a year old a dog is mature enough to breed, unlike a 7-year-old child — and then age more slowly, at a pace that depends on size. The American Veterinary Medical Association (AVMA) states that dogs do not age at a rate of 7 human years per dog year. The ×7 ratio is often said to come from comparing a human lifespan of about 70 years with a dog's of about 10 (AKC). This calculator does not use ×7; it uses the AKC chart and Japan's MOE guideline instead.
Why do large dogs age faster?
Bigger dogs tend to have shorter lives. A study of mortality data from 74 breeds found that large dogs' risk of death rises faster with age, concluding that large dogs die young mainly because they age quickly (Kraus et al., 2013). That is why the charts add more human years per year for large and giant dogs — about 5–7 a year in later life on the AKC chart, versus about 4 for small dogs. Exactly why large dogs age faster is not yet fully understood.
How do you convert cat years to human years?
A cat is about 15 in human years at age 1 and about 24 at age 2, then ages about 4 human years per year — in other words, 24 + (age − 2) × 4. The FelineVMA (Feline Veterinary Medical Association, formerly AAFP) chart and Japan's MOE guideline give the same values. For kittens, 1 month ≈ 1 year, 3 months ≈ 4 years and 6 months ≈ 10 years (FelineVMA). Cats are not split into size classes.
At what age is a dog or cat considered senior?
As a rule of thumb, small and medium dogs from about 8, and large and giant dogs from about 6–7. Japan's MOE puts the start of later life at about 8–10 (6–7 for large dogs). The AVMA considers a dog senior in the last 25% of its breed's estimated lifespan — about 8–11 years for small breeds, 8–10 for medium, 8–9 for large and 6–7 for giant breeds. Cats are "mature adults" at 7–10 and seniors after 10 (FelineVMA, AAHA). Every pet ages differently, and nothing changes overnight at these ages.
What if I don't know my pet's birthday?
Choose "Enter age" and type the age you know, or the age your veterinarian estimated — common for rescue dogs and cats. If you know the adoption date and the estimated age at adoption, add the time since adoption to that age (the Anniversary Calculator shows how many days have passed since a date). Entering a birthday also shows a countdown to the next birthday.
Why do the Japan (MOE) and US (AKC) results differ?
Both are rough guides built in different ways. Japan's MOE uses one formula for small/medium dogs and cats (24 + (age − 2) × 4) and another for large dogs (12 + (age − 1) × 7). The AKC chart uses four weight classes: small, medium and large dogs share the same values up to age 5 (15 at 1, 24 at 2, then 4 a year), and the sizes spread apart from age 6 (giant dogs follow their own values from 12 at age 1). Results are nearly identical for small dogs, but the MOE formula gives higher ages for large dogs. Treat the two as a range rather than an exact answer.
What is the epigenetic clock (UCSD formula)?
Published in 2020 by a team led by the University of California San Diego, it converts dog age with human age = 16 × ln(dog age) + 31, where ln is the natural logarithm. It was derived by comparing DNA methylation — chemical marks on DNA that change with age — in the blood of 104 dogs, mostly Labrador Retrievers, with humans (Wang et al., Cell Systems). It shows that dogs age very quickly early on and then slow down, but the paper notes that breeds with different lifespans could need different conversions. Because the value swings sharply under age 1 (and turns negative before about 7–8 weeks of age), this calculator shows it as a reference for dogs aged 1 and over.
How do I choose between small, medium, large and giant?
Use your dog's adult weight (or the expected adult weight for a puppy). This tool follows the AKC chart's classes: small up to 20 lb (9 kg), medium 21–50 lb (9–23 kg), large 51–100 lb (23–45 kg) and giant over 100 lb (45 kg). For mixed breeds, or breeds such as the Shiba Inu that straddle a boundary, go by actual weight. Japan's MOE guideline has only two classes (small–medium and large), so giant dogs use the large-dog formula there.
How often should my pet have a checkup?
General guidance is at least once a year for adult dogs and cats (every 6–12 months for dogs) and at least every 6 months for seniors (AAHA canine guidelines, AVMA, FelineVMA). For cats, FelineVMA recommends checkups at least every 6 months after age 10. The right schedule depends on your pet's health, so ask your veterinarian. This tool provides general information and is not a substitute for veterinary care.
Is the age or birthday I enter saved or sent anywhere?
No. All calculations run in your browser; the age or birthday you enter is never sent to or stored on a server.

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