Baby age calculator
Your baby's age in months, weeks and days, with adjusted age for babies born early.
- ๐บ๐ธ US federal & state rules
- AAP corrected age guidance
- See sources
Baby's age
7 months, 4 days
31 weeks, 1 day old
- In weeks
- 31 weeks, 1 day
- In days
- 218 days
- Turns 8 months on
- Nov 15, 2026
This is an example. Enter your numbers above and press the button to see your own result.
Milestone dates
| 100 days old | Tue, Jun 23, 2026 (passed) |
|---|---|
| 6 months | Tue, Sep 15, 2026 (passed) |
| 1st birthday | Mon, Mar 15, 2027 |
| 18 months | Wed, Sep 15, 2027 |
| 2nd birthday | Wed, Mar 15, 2028 |
- Months are counted on the calendar, so the baby turns one month older on the same date each month (or the last day of a shorter month).
Show the math
| Born | Sun, Mar 15, 2026 |
|---|---|
| As of | Mon, Oct 19, 2026 |
| Calendar months and days | 7 months, 4 days |
| Next birthday | Mon, Mar 15, 2027 |
What to do next
How it works
Age in months is counted on the calendar: the baby gains a month on the same date each month. When that date does not exist (for example the 31st in a 30-day month), the last day of the month counts. Weeks and days are the total number of days since birth divided by 7.
For a baby born early, adjusted age starts from the original due date instead of the birth date. That is the same as subtracting the weeks born early (40 weeks minus the weeks at birth) from the actual age.
Things to keep in mind
Adjusted age helps set fair expectations for milestones in a premature baby. It is not medical advice, and your pediatrician will tell you which age to use at checkups.
Sources
Rules applied as of 2026-10-19. See the sources below for details.
- HealthyChildren.org (AAP), Corrected Age for PreemiesChecked 2026-10-19
Frequently asked questions
How old is my baby in months?
Count calendar months from the birth date. A baby born March 15 turns 7 months old on October 15, and on October 19 is 7 months, 4 days old.
What is adjusted age for a preemie?
Adjusted (corrected) age is age from birth minus the weeks born early, counted against 40 weeks. A baby born at 32 weeks is 8 weeks early, so at 16 weeks old the adjusted age is 8 weeks, about 2 months.
Until what age should I use adjusted age?
The American Academy of Pediatrics says to use corrected age for development during the first 2 years. After that, most children have caught up.
Why do weeks and months not line up?
A month is 28 to 31 days, so 4 weeks is a little short of a month. 7 months is about 30 weeks, not 28.