Dog Years Calculator
Convert your dog's age to human years using both the simple multiply-by-7 method and the scientifically accurate formula based on DNA methylation.
Our dog years calculator converts your dog's age into human years using two methods: the classic multiply-by-7 rule and the more accurate scientific formula based on DNA methylation research.
How to calculate dog years
The traditional method is simply to multiply your dog's age by 7. So a 3-year-old dog equals 21 human years. It's easy but not very accurate — dogs age much faster in their early years and slower later on.
The scientific method, from a 2019 study published in Cell Systems, uses changes in DNA methylation to align dog and human ageing. The formula is:
Human age = 16 × ln(dog age) + 31
Where ln is the natural logarithm. This formula better reflects that dogs reach maturity very quickly (a 1-year-old dog is roughly equivalent to a 31-year-old human) and then age more slowly relative to humans.
Why the ×7 rule is inaccurate
The ×7 rule assumes dogs and humans age at a constant ratio, but that's not how biology works. A 1-year-old dog is already sexually mature — far beyond what a 7-year-old human has reached. The scientific formula accounts for this non-linear ageing curve and produces more biologically meaningful comparisons.
Dog age comparison table
| Dog age | Simple (×7) | Scientific |
|---|---|---|
| 1 year | 7 | 31 |
| 2 years | 14 | 42 |
| 3 years | 21 | 49 |
| 5 years | 35 | 57 |
| 8 years | 56 | 64 |
| 10 years | 70 | 68 |
| 15 years | 105 | 74 |