Dog Years Converter
Pick the unit you are starting from, enter an age and read the equivalent in the unit you want to see: dog months, dog years, human months or human years.
Related converters
Created by the Reeliy Editorial Team. Last updated: Oct 19, 2026
Using the dog years converter
Type an age in the first box and choose its unit from the drop-down: dog months, dog years, human months or human years. The second drop-down sets what you want to see, and the answer updates as you type. Choosing the same unit twice simply returns your number, rounded to two decimals.
The old rule that one dog year equals seven human years is easy to remember but wrong at both ends of a dog's life. Dogs mature far faster than people in their first two years and then age more slowly. This converter uses a curve fitted to how a dog's DNA changes with age instead of a flat multiplier.
From dog years to human years: the formula
The human-equivalent age follows a natural logarithm of the dog's age in years:
human years = 16 × ln(dog years) + 31ln is the natural logarithm. Dog age in years, answer in human years.
Example: a 5-year-old dog. ln(5) = 1.6094, so 16 × 1.6094 = 25.75, and 25.75 + 31 = 56.75 human years.
Example: a 7-month-old puppy. First convert to years: 7 ÷ 12 = 0.5833. Then ln(0.5833) = −0.539, 16 × (−0.539) = −8.62, and −8.62 + 31 = 22.38. The converter shows this as 22.38 human years, or 268.51 human months.
The curve gives odd numbers for very young puppies, so the converter treats any dog younger than 0.15 years (about eight weeks) as 0.3 human years. Dog months and human months are just the year figures multiplied by 12.
| Dog age (years) | Human age (years) |
|---|---|
| 0.25 | 8.82 |
| 0.5 | 19.91 |
| 1 | 31 |
| 2 | 42.09 |
| 3 | 48.58 |
| 4 | 53.18 |
| 5 | 56.75 |
| 7 | 62.13 |
| 10 | 67.84 |
| 12 | 70.76 |
| 15 | 74.33 |
| 20 | 78.93 |
From human years back to dog years
Going the other way reverses the formula:
dog years = e^((human years − 31) ÷ 16)e is Euler's number, about 2.71828.
For 40 human years that is e^(9 ÷ 16) = e^0.5625 = 1.755 dog years exactly. The converter finds the answer by stepping along the curve in tenths of a dog year and reporting the last step that does not pass your human age, so it shows 1.7 for 40 human years. Human ages below 0.3 years are treated as 0.15 dog years, and human months are divided by 12 before the search.
That means human-to-dog answers move in 0.1-year (about 5-week) steps. Treat them as a rough guide rather than a precise date.
Dog aging varies with breed, size and health. Large breeds tend to have shorter lives than small ones, so any single formula is an estimate. For medical or care decisions talk to a veterinarian. See our disclaimer.
For a calculator-style version of the same idea, see the dog years calculator.
Frequently asked questions
How old is a 1-year-old dog in human years?
By the formula 16 × ln(dog age) + 31, a dog of exactly one year is 31 human years, because ln(1) = 0.
Is one dog year really seven human years?
No. Seven is a rough average that fits a mid-life dog. The first year of a dog's life is worth about 31 human years and the second adds roughly 11 more, after which each extra dog year adds less.
How do I convert dog months to human years?
Choose Dog Months as the starting unit and Human Years as the target. The tool divides the months by 12 first, then applies the logarithmic formula.
Why does the human-to-dog answer jump in steps?
The converter searches along the age curve in 0.1-year increments, so the result is a multiple of 0.1 dog years (or 1.2 dog months).
References
- Wang, T. et al. (2020). Quantitative translation of dog-to-human aging by conserved remodeling of the DNA methylome. Cell Systems, 11(2).
Cite this converter and page
If you use this page in your work, you can cite it as:
Reeliy Editorial Team. (2026). Dog Years Converter. Reeliy. https://reeliy.com/converters/dog-years-converter“Dog Years Converter.” Reeliy, 2026, https://reeliy.com/converters/dog-years-converter.