Puppy age calculator: months to human years
Those first months go quickly. Enter 0 years and your puppy’s age in months, or use a birthday to see a simple human-age comparison.
Puppy age in months: human-year estimates
| Puppy age | Human-age estimate |
|---|---|
| 1 month | 2 |
| 2 months | 3 |
| 3 months | 5 |
| 4 months | 7 |
| 5 months | 8 |
| 6 months | 10 |
| 7 months | 11 |
| 8 months | 12 |
| 9 months | 13 |
| 10 months | 13 |
| 11 months | 14 |
| 12 months | 15 |
All four size tables share the same first-year points in this model. Monthly estimates are rounded interpolations between birth, 6 months (10 human years), and 12 months (15). They are not observed developmental milestones.
Entering months without rounding up
For a 9-month-old puppy, enter 0 years and 9 months. For a dog aged 1 year and 3 months, enter 1 year and 3 months. If you know a birthday, choose Enter birthday and the calculator will work out completed years and months.
Why puppy size still appears in the calculator
Choose your puppy’s expected adult size. The first-year estimates are identical in our four size tables, but the choice matters for later ages and saved results. Current puppy weight is not the same as expected adult size.
Human years are a comparison, not a puppy schedule
A number such as 10 human years does not mean a puppy behaves like a 10-year-old child or is physically mature. AAHA’s approach considers life stage and individual differences. Use your puppy’s actual age and veterinary guidance when planning care.
If the birthday is only an estimate
An adoption record may give an approximate birth date. You can enter an age directly and update it later. The calculator cannot infer a puppy’s true age from breed, size, behavior, or a photo.
Keep a little record as they grow
After calculating, you can add a name or photo, save a pet on this device, and download a result image. Birthday-based saved ages refresh when you revisit. If you entered a manual age, edit it as your puppy grows.
Common questions
How old is a 3-month-old puppy in human years?
Our simplified table estimates about 5 human years. This comes from interpolation before the 6-month point, so it should not be interpreted as a developmental assessment.
How old is a 9-month-old puppy in human years?
The model gives about 13 human years after rounding. Use the calculator to enter 0 years and 9 months.
Can I enter a puppy’s age in weeks?
This calculator uses completed calendar months rather than weeks. If you know the birth date, birthday mode is the better option. For an age under one completed month, this tool is not suitable.
When does my puppy become an adult?
This human-year chart cannot determine that. Maturity varies with breed, expected size, and the individual dog. Ask your veterinarian about your puppy’s life stage.
Sources and calculation notes
Written by PetAgeNow. Numbers come from our own calculator tables. Veterinary resources provide life-stage context and do not endorse or validate this calculator.
Age comparisons are educational estimates. They do not predict health, behavior, or lifespan.