Dog Age Chart: Dog Years to Human Years by Size
This dog age chart shows your dog's age in human years for every age from 1 to 16, across all four adult sizes. It uses the size-based conversion vets rely on — 15 human years for year one, 24 by year two, then 4 to 7 more per year depending on size — not the debunked "multiply by 7" rule.
Dog Years to Human Years Chart (All Sizes)
| Dog age | Small | Medium | Large | Giant |
|---|---|---|---|---|
| 1 | 15 | 15 | 15 | 15 |
| 2 | 24 | 24 | 24 | 24 |
| 3 | 28 | 29 | 30 | 31 |
| 4 | 32 | 34 | 36 | 38 |
| 5 | 36 | 39 | 42 | 45 |
| 6 | 40 | 44 | 48 | 52 |
| 7 | 44 | 49 | 54 | 59 |
| 8 | 48 | 54 | 60 | 66 |
| 9 | 52 | 59 | 66 | 73 |
| 10 | 56 | 64 | 72 | 80 |
| 11 | 60 | 69 | 78 | 87 |
| 12 | 64 | 74 | 84 | 94 |
| 13 | 68 | 79 | 90 | 101 |
| 14 | 72 | 84 | 96 | 108 |
| 15 | 76 | 89 | 102 | 115 |
| 16 | 80 | 94 | 108 | 122 |
How to Read the Chart
Find your dog's age in the left column, then read across to the column for its adult size — the size your dog is (or will be) fully grown:
- Small / Toy (under 20 lbs / under 9 kg) — adds 4 human years per dog year after age 2; senior at around 10.
- Medium (20 to 50 lbs / 9 to 23 kg) — adds 5 human years per dog year after age 2; senior at 8 to 10.
- Large (50 to 100 lbs / 23 to 45 kg) — adds 6 human years per dog year after age 2; senior at 6 to 8.
- Giant (over 100 lbs / over 45 kg) — adds 7 human years per dog year after age 2; senior at 5 to 6.
The columns are identical for years 1 and 2 because all dogs mature at the same rate early on; size only changes the pace from year three. If your dog's age falls between two rows, or you want the result without any mental math, use the dog age calculator — it handles months and partial years and tells you your dog's life stage. There's also a quick dog years to human years converter if you just want the conversion steps.
Get an Exact Number for Your Dog
Choose the size your dog will reach when fully grown. Always use adult size, even for a puppy. A Great Dane puppy is Giant from day one.
Frequently Asked Questions
Find your dog’s age in the left column, then read across to the column matching its adult size (small, medium, large, or giant). The number in that cell is your dog’s approximate age in human years.
Use adult weight: Small is under 20 lbs (9 kg), Medium is 20–50 lbs (9–23 kg), Large is 50–100 lbs (23–45 kg), and Giant is over 100 lbs (45 kg). For a puppy, always use the size it will reach fully grown.
All dogs mature at roughly the same speed for their first two years — about 15 human years in year one and 24 by the end of year two. Size only starts to change the pace from year three onward.
Interpolate: a 3 year 6 month medium dog is the year-3 value (29) plus half of the next year’s increment (+2.5), so about 31–32 human years. The calculator handles these partial years automatically.