Dog age calculator
Dogs age fast early, slower later, and faster if they are big. This page gives both respected conversions — and labels which is which, unlike sites that quietly pick one.
🐶 Dog age calculator
Size-based (AKC chart)
36 yrs
UCSD science formula
57 yrs
Life stage: Adult
Two honest numbers, two different bases. The size-based figure is looked up from the AKC's published chart: every size is the same through age 5 (36 human years) and the sizes only diverge from age 6, because larger dogs age faster later in life — it knows about size, so it drives the life-stage label. Whole years use AKC's exact chart values (AKC publishes ages 1–16); part-years are filled in by straight-line interpolation between chart years, and ages 17 and over extend the chart's final yearly step. The UCSD formula — 16 × ln(age) + 31, from DNA methylation research on Labradors — captures how fast dogs age early, but knows nothing about size. Neither is your dog's medical age.
Dog years to human years chart (size-based)
| Dog age | Small | Medium | Large | UCSD formula |
|---|---|---|---|---|
| 1 yr | 15 | 15 | 15 | 31 |
| 2 yr | 24 | 24 | 24 | 42 |
| 3 yr | 28 | 28 | 28 | 49 |
| 5 yr | 36 | 36 | 36 | 57 |
| 7 yr | 44 | 47 | 50 | 62 |
| 10 yr | 56 | 60 | 66 | 68 |
| 12 yr | 64 | 69 | 77 | 71 |
| 15 yr | 76 | 83 | 93 | 74 |
Size columns: the AKC chart's own published values — all sizes are identical through age 5 (36) and diverge from age 6. AKC publishes whole-year values for ages 1–16; the calculator interpolates part-years in a straight line between chart years and extends the chart's final yearly step for ages 17 and over. Last column: UCSD formula, size-blind, from Labrador DNA methylation data. Sources on the About page, checked 30 Oct 2026.
Next: how much should this dog eat?
Age and size set the life stage; weight and life stage set the calories. Use the feeding calculator for a daily kcal, cups and grams figure.