Pop in your baby or child's birthday and we'll work out exactly how old they are today — in years, months, weeks and days.
Enter their date of birth above and we'll show their exact age in years, months, weeks and days as of today, updated the moment you pick a date — along with a countdown to their next birthday.
The "weeks old" figure above is their total age in complete weeks since birth — handy for the first year or so, when milestones and feeding guidance are often described by week rather than month.
The "months old" figure counts complete calendar months since their date of birth, the same way you'd count an adult's age in years — so a baby born on the 10th turns "1 month old" on the 10th of the following month, regardless of how many days that month has.
This calculator shows age as of today rather than a future date, but you can approximate it yourself by counting forward from their birth date, or use our Weeks From Today Calculator to count forward from today in weeks instead.
We take today's date and their date of birth and count the difference three ways at once: total days (converted into weeks), and complete years and months using calendar-based counting — the same method used for describing an adult's age, just scaled down to a baby's shorter timeline.