How to use the puppy & kitten age calculator
- Enter the birth date.
- Optional: pick a different date to see the age on that day.
- Press Calculate.
Worked example
A puppy born on 26 July 2026, checked on 18 October 2026.
- Birth date
- 2026-07-26
- Age on this date (leave empty for today)
- 2026-10-18
- Weeks and days
- 12 weeks
- Total days
- 84
- Months and days
- 2 months 22 days
Use the age in weeks in the Puppy Food or Kitten Food calculator.
Example values are illustrative; this result is produced by the same calculator above.
How we calculate it
Sources: Pure arithmetic / unit conversion on user inputs (no external constant)
Understanding your result
Age in weeks matters for puppies and kittens because feeding amounts, meals a day and vet schedules change quickly in the first months. The calculator counts the days from the birth date to today, or to a date you choose, and shows the result in weeks, months and days.
For example, a puppy born on 26 July 2026 is 84 days old on 18 October 2026. That is exactly 12 weeks, or 2 whole months and 22 days. Months are counted as calendar months, so the leftover days depend on the dates.
If you do not know the exact birth date, ask your vet or the rescue for their estimate and use that date. The age in weeks can then go straight into the Puppy Food or Kitten Food calculator.
Common mistakes
- Using the date you brought the puppy home instead of the birth date.
- Rounding up the weeks. The calculator rounds down to whole completed weeks.
- Mixing up day and month when typing the date. Use the date picker where you can.
- Using an estimated birth date as if it were exact; treat results as approximate.
- Comparing a puppy's age in weeks with a human-year age; they measure different things.
Good to know
- For older pets use the Dog Age Calculator or Cat Age Calculator to see human-year equivalents and life stage.
- Small and giant breeds grow at different speeds, so ask your vet about your puppy's expected adult size.
- Keep the birth date with your pet's records; it is handy for vaccination and microchip paperwork.
Frequently asked questions
How do I work out my puppy's age in weeks?
Count the days from the birth date to today and divide by 7, rounding down. The calculator does this for you and also shows months and days.
What if I do not know the birth date?
Use your vet's estimate of the age and pick a birth date that gives that age. Rescues often record an estimated birth date.
Why does age in weeks matter?
Feeding amounts and meal numbers for puppies and kittens depend on their age in weeks, as in the Puppy Food and Kitten Food calculators.
Can I check my pet's age on a past or future date?
Yes. Pick a date in the second box. Leave it empty to use today.
Does this work for kittens too?
Yes. It counts days from the birth date, so it works for any young animal. Use the Kitten Food Calculator for feeding amounts.
How far back can the birth date be?
Up to 25 years, so it also works for older pets. For human-year equivalents use the Dog Age Calculator or Cat Age Calculator.
Sources
- Pure arithmetic / unit conversion on user inputs (no external constant)
Guides about this
Related calculators
- Puppy Food CalculatorCalculate how much a growing puppy needs, how many meals a day, and how much per meal.
- Kitten Food CalculatorFind out how many calories a growing kitten needs and how much food that is.
- Dog Age CalculatorConvert your dog's age into human years, taking size into account.
- Cat Age CalculatorConvert your cat's age into human years and see its life stage.
Estimates only. Every pet is different — confirm with your veterinarian.