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The science behind our calculator

"1 dog year = 7 human years" isn't true. It's an old myth. Dogs don't all age at the same speed — a Great Dane and a Yorkshire Terrier grow old completely differently.

So what do we do instead? We look at how long each breed typically lives. Breeds that don't live as long age faster; breeds that live longer age more slowly. We also don't jump straight from "puppy speed" to "adult speed" — the aging rate changes smoothly over time, just like it does in real life, instead of suddenly switching on one birthday.

Where do the numbers come from? We've built this calculator using real scientific research into dog lifespans, led by a 2024 study of over 580,000 UK dogs from Dogs Trust and Liverpool John Moores University — including its complete published results for 155 breeds, not just a summary — plus further research from the Royal Veterinary College, to make it as accurate as we possibly can.

We believe this is one of the most carefully built dog age calculators out there. But every dog is different, and we can't guarantee it'll be exactly right for yours. What we can promise is that it's our most careful, most accurate attempt, based on the best available scientific data.