Dog age calculator
Your dog's age in human years by size, with life stage and the DNA-based formula.
- ๐บ๐ธ US federal & state rules
- AVMA chart, AAHA life stages
- See sources
In human years
About 36
5 years old, from the AVMA chart for a medium dog
- Life stage (AAHA)
- Mature adult
- Senior age for a medium dog (AVMA)
- 8 to 10 years
- DNA-based formula (Labradors)
- About 57
- Suggested vet visits
- Every 6 to 12 months
This is an example. Enter your numbers above and press the button to see your own result.
Older dogs by size (AVMA human-age ranges)
| 7 years | 44 (small dog) to 56 (giant dog) |
|---|---|
| 10 years | 56 (small dog) to 78 (giant dog) |
| 15 years | 76 (small dog) to 115 (giant dog) |
| 20 years | 96 (small dog) to 120 (giant dog) |
Dog years to human years (AVMA medium dog chart)
| 1 year | 15 (formula 31) |
|---|---|
| 2 years | 24 (formula 42) |
| 3 years | 28 (formula 49) |
| 4 years | 32 (formula 53) |
| 5 years (now) | 36 (formula 57) |
| 6 years | 42 (formula 60) |
| 7 years | 47 (formula 62) |
| 8 years | 51 (formula 64) |
| 9 years | 56 (formula 66) |
| 10 years | 60 (formula 68) |
| 11 years | 65 (formula 69) |
| 12 years | 69 (formula 71) |
| 13 years | 74 (formula 72) |
| 14 years | 78 (formula 73) |
| 15 years | 83 (formula 74) |
| 16 years | 87 (formula 75) |
- Bigger dogs age faster after the first few years. A large or giant dog will usually be older in human terms than the medium-dog chart shows, and a small dog younger. The size ranges above show how wide the gap gets.
- The DNA-based formula comes from 104 Labrador retrievers, so it may not fit other breeds.
- These are rough estimates for fun and planning, not a health assessment. Ask your vet how your dog is aging.
Show the math
| Dog's age | 5 years (5 years) |
|---|---|
| AVMA chart (medium dog, 21 to 50 lb) | 36 human years |
| 16 ร ln(age) + 31 | 16 ร ln(5) + 31 = 56.8 |
| Size | Medium (20 to 50 lb) |
What to do next
How it works
The main number comes from the AVMA dog age chart, which is based on a medium-sized dog of 21 to 50 lb. Between whole years, the calculator splits the difference by months. Under 1 year it spreads 0 to 15 human years evenly.
The second number uses the formula from Wang and colleagues (2020): human age = 16 ร ln(dog age) + 31. It tends to run higher for young adult dogs and lower for old dogs than the chart.
Things to keep in mind
Size matters more as dogs get older. The AVMA's own ranges for older dogs are shown by size because a single chart cannot fit a Chihuahua and a Great Dane. These numbers are estimates and say nothing about your dog's health.
Sources
Rules applied as of 2026-10-09. See the sources below for details.
- AVMA, Pets age faster than people (dog age chart)Checked 2026-10-09
- AVMA, Caring for senior cats and dogs (senior age by size)Checked 2026-10-09
- 2019 AAHA Canine Life Stage GuidelinesChecked 2026-10-09
- Wang et al. (2020), Quantitative Translation of Dog-to-Human Aging, Cell SystemsChecked 2026-10-09
Frequently asked questions
Is one dog year really 7 human years?
No. The AVMA chart puts a 1-year-old dog at about 15 human years and a 2-year-old at 24. After that it adds roughly 4 to 5 years per dog year for a medium dog.
Do big dogs age faster?
Yes, after the first couple of years. The AVMA puts a 10-year-old small dog at about 56 human years and a 10-year-old giant dog at about 78.
What is the 16 ln(age) + 31 formula?
It comes from a 2020 study of DNA changes in 104 Labrador retrievers. A 5-year-old dog works out to 16 ร ln(5) + 31, about 57 human years.
When is a dog a senior?
It depends on size. The AVMA gives about 8 to 11 years for small dogs, 8 to 10 for medium, 8 to 9 for large and 6 to 7 for giant breeds.