Dog age calculator: how old is your dog in human years?
Enter your dog's age and breed or size. You get the age in human years from the AVMA size chart, plus your dog's life stage.
- Free, no sign-up
- Nothing is uploaded
- Based on the AVMA chart
How old is my dog in human years?
It depends on your dog's size. A 5 year old small dog is about 36 in human years, a 5 year old large dog is about 40, and a 5 year old giant dog is about 45. The calculator above reads these numbers from the chart below and fills in the months between.
The shortcut "multiply by 7" gets the middle of a dog's life roughly right and almost everything else wrong. Dogs grow up in about two years, then age more slowly, and larger dogs age faster than small ones.
Dog years to human years chart
This is the size-based chart from the American Veterinary Medical Association. Find your dog's age in the left column and read across to the size group.
| Dog age | Small up to 20 lb |
Medium 21 to 50 lb |
Large 51 to 90 lb |
Giant over 90 lb |
|---|---|---|---|---|
| 1 | 15 | 15 | 14 | 12 |
| 2 | 24 | 24 | 22 | 22 |
| 3 | 28 | 28 | 29 | 31 |
| 4 | 32 | 32 | 34 | 38 |
| 5 | 36 | 36 | 40 | 45 |
| 6 | 40 | 42 | 45 | 49 |
| 7 | 44 | 47 | 50 | 56 |
| 8 | 48 | 51 | 55 | 64 |
| 9 | 52 | 56 | 61 | 71 |
| 10 | 56 | 60 | 66 | 79 |
| 11 | 60 | 65 | 72 | 86 |
| 12 | 64 | 69 | 77 | 93 |
| 13 | 68 | 74 | 82 | 100 |
| 14 | 72 | 78 | 88 | 107 |
| 15 | 76 | 83 | 93 | 114 |
| 16 | 80 | 87 | 99 | 121 |
How the calculator works
You give an age and a size, or a breed. When you pick a breed, we look up its usual adult weight and use that size group. Mixed breeds should choose by weight. Everything runs in your browser, so nothing is sent anywhere.
- Your dog's age in years and months becomes one number, like 5.5 years.
- We find that age in the chart for your size group.
- For ages between two rows, we draw a straight line between them. For a puppy under 1, we scale up to the first row.
- The reverse mode runs the same lines the other way, from a human age to a dog age.
The chart stops at 16. Past that, we keep the last step going, which is a fair guess for the few dogs that get there.
Why size matters so much
Small dogs often live to 14 or 15. Giant breeds like the Great Dane are often old by 7 or 8. The first two years look the same for every dog: a 1 year old is a teenager and a 2 year old is a young adult. After that, a giant dog adds around seven human years a year, while a small dog adds about four.
That is why a Chihuahua and a Saint Bernard of the same age are in very different places in life. If you are not sure of your dog's breed, our dog breed identifier can find the closest match from a photo, and you can bring it back here. See every breed we know on the breeds page.
Puppy, adult and senior: the life stages
Life stage tells you more than the number. It decides food, exercise and how often to see the vet. The ages below are a rule of thumb, not part of the AVMA chart.
- Puppy: from birth to about 1 year. Giant breeds take up to 2 years to finish growing.
- Adult: from the end of growth until the senior years. This is the longest stretch of a dog's life.
- Senior: from about 6 years for giant dogs, 7 for large, 8 for medium and 10 for small dogs.
Method and source
The chart comes from the American Veterinary Medical Association, which publishes a dog age chart split into four weight groups: up to 20 pounds, 21 to 50, 51 to 90, and over 90. We use those groups and values as they are. Breed sizes are our own grouping by typical adult weight, so a particular dog can fall a class either way.
Fractions of a year are estimates made by drawing a straight line between two chart rows. The result is a guide for fun and for planning care. It is not a medical opinion. Your vet knows your dog best.
Source: American Veterinary Medical Association, dog age chart (avma.org).