# Dog Age Calculator

A dog's age in human years, using the epigenetic formula of Wang et al. (2020): human age ≈ 16 × ln(dog age) + 31. A one-year-old dog is about 31 in human years — not 7.

| Dog age | Human years |
|---|---|
| 1 year | 31 |
| 2 years | 42 |
| 3 years | 49 |
| 4 years | 53 |
| 5 years | 57 |
| 6 years | 60 |
| 7 years | 62 |
| 8 years | 64 |
| 10 years | 68 |
| 12 years | 71 |
| 14 years | 73 |
| 16 years | 75 |

## Common questions

### How many dog years is one human year?

There isn’t one number, because dogs don’t age at a steady rate. Using the epigenetic clock published by Wang et al. (2020), a one-year-old dog is already about 31 in human years, while the step from 10 to 11 adds closer to 1.5. The first year counts for a great deal; every year after it counts for less.

### How do dog years work?

Wang et al. compared DNA methylation — chemical marks that accumulate on DNA with age — in 104 Labrador retrievers against the same marks in humans. The match is logarithmic, not linear: human age ≈ 16 × ln(dog age) + 31. That is the formula this calculator uses.

### Is the “multiply by seven” rule true?

No. It would make a one-year-old dog seven in human years; the methylation clock puts it near 31. At the other end it overshoots: a 15-year-old dog would be 105, where the formula gives 74. The rule of seven is a rounding of average lifespans, not a measurement of aging.

### Why does the calculator start at one year?

The formula is logarithmic, so below one year it returns numbers with no meaning. Puppy development in the first months is better described by growth stage than by a human-age equivalent.

### Does breed or size change the answer?

The study measured 104 Labrador retrievers, so this formula does not model breed differences. Larger breeds are generally shorter-lived, and this number will read young for a giant breed and old for a small one. We publish the formula the study actually supports rather than adjusting it by breed with no source.

## Sources

- Wikidata — dog breed mass (property P2067) — Wikimedia Foundation, query run 2026-07-22, CC0 license (https://query.wikidata.org/)
- Wikidata — cat breed mass (property P2067) — Wikimedia Foundation, query run 2026-07-28, CC0 license (https://query.wikidata.org/)
- Breed weights — official AKC breed standards — American Kennel Club, breed pages, accessed 2026-07-29 (https://www.akc.org/dog-breeds/)
- Quantitative Translation of Dog-to-Human Aging by Conserved Remodeling of the DNA Methylome — Wang et al., Cell Systems, 2020, vol. 11, no. 2, p. 176–185.e6 (DNA methylation in 104 Labradors) (https://doi.org/10.1016/j.cels.2020.06.006)
- Body-Weight Changes during Growth in Puppies of Different Breeds — Hawthorne et al., Journal of Nutrition, 2004, vol. 134, p. 2027S (https://doi.org/10.1093/jn/134.8.2027S)
- Management of Reproduction — gestation period in the bitch — Merck Veterinary Manual, “Approximate Gestation Periods” table, accessed 2026-07-23 (https://www.merckvetmanual.com/multimedia/table/approximate-gestation-periods)
- Dystocia in Small Animals — Merck Veterinary Manual, “Diagnosis of Dystocia in Small Animals” section, accessed 2026-07-28 (https://www.merckvetmanual.com/reproductive-system/reproductive-diseases-of-the-female-small-animal/dystocia-in-small-animals)
- Factors affecting gestation duration in the bitch — Eilts et al., Theriogenology, 2005, vol. 64, no. 2, p. 242–251 (https://pubmed.ncbi.nlm.nih.gov/15955350/)
- Nutritional Requirements of Small Animals — energy requirements of the dog and cat — Merck Veterinary Manual, “Energy” section, accessed 2026-07-23 (https://www.merckvetmanual.com/management-and-nutrition/nutrition-small-animals/nutritional-requirements-of-small-animals)
- Chocolate Toxicosis in Animals — Merck Veterinary Manual, “Methylxanthine Content of Various Types of Chocolate” table and “Etiology” section, accessed 2026-07-28 (https://www.merckvetmanual.com/toxicology/food-hazards/chocolate-toxicosis-in-animals)
- ASPCA Poison Control — ASPCA, 24-hour emergency line, accessed 2026-07-28 (https://www.aspca.org/pet-care/aspca-poison-control)
- How old is your cat? — life stage and human equivalent age — International Cat Care (Cat Friendly Clinic), accessed 2026-07-28 (https://icatcare.org/resources/cat-friendly-clinic/how-old-is-your-cat-handout.pdf)
- The Special Needs of the Senior Cat — cat age in human years — Cornell Feline Health Center, Cornell University, accessed 2026-07-28 (golden-test source, not used to build the calculation) (https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/special-needs-senior-cat)
- Calorie Needs for an Average Healthy Adult Cat in Ideal Body Condition — WSAVA Global Nutrition Committee, updated July 2020 (golden-test source, not used to build the calculation) (https://wsava.org/wp-content/uploads/2020/07/Calorie-Needs-for-Healthy-Adult-Cats-updated-July-2020.pdf)
- Assessment of body weight for age determination in kittens — DiGangi et al., Journal of Feline Medicine and Surgery, 2019 (tables 1 and 2, weight-for-age, male and female) (https://doi.org/10.1177/1098612X19844846)
- Kitten Age & Weight Chart — ASPCA Pro, 2023 (golden-test source, not used to build the calculation) (https://www.aspcapro.org/sites/default/files/2023-08/aspca_kittenchart_2023.pdf)

Full method: https://petmeasure.com/sources

_Verified 2026-07-28. Estimates only — this does not replace veterinary advice._