Baby Age Calculator
About Baby Age Calculator
Why Track Baby's Age in Weeks?
During the first two years of life, development happens so rapidly that measuring age in weeks provides much more precision than months alone. Pediatricians track milestones in weeks during the first year because a 4-week-old and a 7-week-old baby are at very different developmental stages despite both being one month old. Vaccination schedules, growth chart assessments, and developmental screening tools all rely on exact age in weeks. This calculator instantly converts your baby's birth date into their precise age in multiple formats.
How This Calculator Works
Enter your baby's date of birth and the calculator instantly shows their age in total days, weeks and days, months and days, and years, months, and days. It also identifies their current developmental stage and upcoming milestones to watch for. For premature babies, you can enter the due date to calculate adjusted age, which pediatricians use for milestone assessment until age 2.
Developmental Milestones
Key milestones by age: Social smile (6-8 weeks), holds head up (3-4 months), rolls over (4-6 months), sits without support (6-8 months), crawls (7-10 months), first words (10-14 months), walks independently (9-15 months), combines words (18-24 months). Remember that all babies develop at their own pace and ranges are wide.
Frequently Asked Questions
What is adjusted age for preemies?
Adjusted age subtracts the weeks of prematurity from the baby's actual age. A baby born 8 weeks early who is 6 months old has an adjusted age of 4 months. Use adjusted age for milestone comparisons until age 2.
When should I be concerned about milestones?
Milestones have wide normal ranges. Contact your pediatrician if your baby is significantly behind on multiple milestones or seems to be losing skills they previously had.
How do I count baby months?
Baby turns 1 month on the same date one calendar month after birth. Born January 15 means 1 month on February 15. This calculator handles months with different lengths automatically.
