Loading calculator...
Loading calculator...
Convert dog years to human years with a size-based dog age calculator. See how old your dog is in human years (or your age in dog years), plus life stage and milestone context for small, medium, and large dogs.
Pick your age as a dog, or your dog's age as a human
Use 0.5 for 6 months, 1 for 1 year, etc.
Your dog's size, or 'if you were a dog' for the other mode
Pro tip: Bookmark this page to quickly access your favorite calculator anytime.
Is your dog a goofy teenager, a full-grown adult, or secretly a senior? The old 7x rule misses how dogs really age. This Dog Age Calculator uses size-based aging to give a better human-year estimate, with life-stage context and milestone-style results.
The old "one year equals seven" idea is not accurate. This dog age calculator uses a size-based method so you get a better sense of your dog's life stage, from puppy to senior. That can help with decisions about vet visits, diet and exercise.
The tool is free and works for any dog. For more on the science behind dog years and human years, see our blog post linked below.
Read more: How Dogs Really Age. Try our Weight to Animals Calculator or Height to Landmarks Calculator.
Our calculator uses proven formulas and up-to-date data to give you accurate results. Here's a transparent look at the methodology behind your calculation.
The Formula
First year: dog age × 15 human yearsSecond year: 15 + (dog age minus 1) × 9, so by age 2 about 24 human yearsAfter age 2: 24 + (dog age minus 2) × multiplier. Multiplier: small 4, medium 5, large 6Human to dog: we reverse the formula using the same multipliersThe 7-year rule fails because dogs age in a sprint early (about 24 human years by age 2), then slow down, and large dogs age faster than small dogs. We use a standard approach: first two years are about 24 human years total, then each extra year adds 4 to 6 human years depending on size. The calculator works both ways (dog to human or human to dog).
Pick whether you want your dog's age in human years or your age in dog years, then enter the age and dog size.
We use the first-year and second-year rules, then the size-based multiplier (4, 5 or 6 human years per year) for ages over two.
The calculator shows the result, life stage and tips. You can change size or age and recalculate.
Disclaimer: Results are estimates based on the information provided. For professional advice, consult with a qualified expert in the relevant field. This calculator is for informational purposes only.