Your Baby's Age Is
Tracking Milestones
Knowing the age in weeks is great for tracking early development milestones!
How The Age is Calculated
The baby age calculator determines the time elapsed between the baby's date of birth and today's date, presenting it in two common formats for tracking early development.
- Weeks & Days: This is the most common format for tracking newborns. The calculator finds the total number of days lived, divides it by 7 to get the full weeks, and the remainder is the number of extra days.
- Months & Days: For this format, the calculator determines the number of full calendar months that have passed since birth, and then counts the remaining days.
Example Calculation
Using the date of birth you provided, here's how we calculated the age:
- Date of Birth: September 19, 2025
- Current Date: March 20, 2026
First, we calculated the total number of days between these two dates. Dividing this total by 7 gives us 26 full weeks with 0 days left over.
Separately, we calculated the number of full months and remaining days between the dates to get 6 months and 1 days.
Frequently Asked Questions
Find answers to common questions about this calculator below.
Other Date & Lifecycle Calculators
Three-Month Checkup
A baby born a little over three months ago coming in for a routine pediatric visit.
Date of Birth: December 16, 2025
Today: March 20, 2026
13w 3d
Weeks & Days
3m 4d
Months & Days
How the calculation is done
- Count the days from birth to today: 94 days.
- Divide by 7 to get full weeks (13) and note the remainder (3 days).
- Use calendar months between the dates to find 3 months with 4 extra days.
Two-Week Newborn
A newborn heading to their two-week check-in with the doctor.
Date of Birth: March 5, 2026
Today: March 20, 2026
2w 1d
Weeks & Days
0m 15d
Months & Days
How the calculation is done
- Count the days from birth to today: 15 days.
- Divide by 7 to get full weeks (2) and note the remainder (1 days).
- Use calendar months between the dates to find 0 months with 15 extra days.