This article was updated on October 16th, 2026
There are two ways to calculate your dog’s age in human years:
1. Know dog’s breed? whether purebred or mixed breed, we recommend using our dog age calculator below for a personalized and accurate estimate.
2. Don’t know your dog’s breed exactly? you can use our dog age chart based on your dog’s size and weight instead.
1. Know Your Dog’s Breed? Use Our Dog Age Calculator
We’ve built one of the most accurate dog age calculators available, using breed-specific estimates to give you the most precise estimate of your dog’s age in human years when you know their breed.
Unlike simpler calculators, ours takes into account several key factors identified by research, including your dog’s breed, neutering status, and whether your dog is male or female. By considering all these factors, our calculator provides a precise estimate of your dog’s age in human years:
Small breeds live as much as 50-80% longer than larger breeds and experience the negative effects of aging later in life compared to large breeds. If your dog is a mixed breed, a reliable way to convert your dog’s age to human years is to use your dog’s size or weight.
2. Don’t Know Your Dog’s Breed? Estimate Human Years Using Your Dog’s Size
All in all trying to figure out how old your dog is in ‘dog years’ v ‘human years’ isn’t an exact science. If your dog is mixed breed or if you don’t know your dog’s breed, the next most important factor to consider is size/weight.
To make it a little easier, we have put together this table that translates ‘dog years’ to ‘human years’ for small, medium and large breeds.
| Your Dog’s Age | Human Years for Small Dogs | Human Years for Medium Dogs | Human Years for Large Dogs |
|---|---|---|---|
| 1 year | 18 | 16 | 14 |
| 2 years | 25 | 24 | 21 |
| 3 years | 28 | 29 | 27 |
| 4 years | 32 | 34 | 32 |
| 5 years | 36 | 38 | 42 |
| 6 years | 40 | 42 | 48 |
| 7 years | 44 | 48 | 57 |
| 8 years | 48 | 54 | 63 |
| 9 years | 52 | 59 | 70 |
| 10 years | 56 | 63 | 75 |
| 11 years | 60 | 68 | 82 |
| 12 years | 64 | 74 | 90 |
| 13 years | 68 | 79 | 100 |
| 14 years | 72 | 83 | 108 |
| 15 years | 76 | 89 | 115 |
| 16 years | 80 | 95 | 120 |
See this infographic to find out your dog’s age in human years based on size:
But if you don’t know when your dog was born, how can you best estimate your dog’s age? Read our post on “How Old Is My Dog?” for easy tips to estimate how old your dog really is.
Studies Used to Build Our “Dog Years to Human Years” Calculator
Estimating a dog’s age in human years is not simple. We have reviewed data from multiple studies to conclude that a breed-based calculator is best. To build the formula behind our calculator, we have used the following studies:
- Mortality in over 350,000 insured Swedish dogs from 1995-2000.
- Lifespan of companion dogs seen in three US veterinary clinics.
- Mortality data on 5663 deceased dogs registered with the UK Kennel Club.
- “Do Female Dogs Age Differently Than Male Dogs?” from The Journal of Gerontology.
- Longevity and Mortality of Dogs in England in The Journal Of Veterinary Medicine.
Related posts: Pictures of Teeth by Dog’s Age: Veterinarians use many clues to estimate a dog’s age. One thing that we examine is the dog’s teeth. In this article, we will review what teeth can tell you about a dog’s age – with pictures of teeth by dog age.
Don’t Use the 7x Rule to Calculate Your Dog’s Age in Human Years
Many people think that a dog year is equivalent to 7 human years. However, this 7x ratio is NOT true for most breeds. For example, a 10-year-old male neutered Chihuahua would be 70 years old using the 7x rule. In reality, our calculator below shows that 45 years old is a better estimate (Chihuahuas have an average life expectancy of 15.5 years).
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