About DogYearsByBreed

Why we built this site

Many people still use the rule that one dog year equals seven human years. It's easy to remember, but it gives misleading answers — especially for young dogs and large breeds. At the same time, it's hard to find an explanation that is easy to follow and accounts for the fact that a Chihuahua and a Great Dane age completely differently.

We built DogYearsByBreed to bring this together in one place: a calculator that uses an open, explained model, and pages that tell you what the number means for your particular dog.

Our goal

The goal isn't to give you a 'correct' number, but to help you understand which life stage your dog is in — and what is often worth thinking about at that stage. We try to be clear about what the model is based on, and just as clear about what it can't tell you.

What you can use the site for

• Get an estimate of your dog's age in human years.
• See whether your dog is normally considered a puppy, adult, mature or senior at its age.
• Read about aging, life expectancy and common topics for individual breeds.
• Understand why the 1:7 rule doesn't hold up, and how the calculation actually works.

How the calculator is maintained

The calculator, the homepage table, the worked examples and the age charts on the breed pages all use one and the same calculation function. When the model is adjusted, it changes in one place and every page updates at the same time. So you should never find two different explanations of how the calculator works.

The sources behind the model are reviewed regularly. When we have actually reviewed the content, we update the 'Last reviewed' date on the methodology page. If we find errors — or users tell us about them — we fix them.