Your baby, month by month.
Twelve little dates worth remembering. Enter a birth date to see when each calendar month begins, without turning weeks into approximate months.
Your twelve calendar anniversaries
Enter a date to see all twelve anniversaries. Dates stay in this browser.
Type YYYY-MM-DD or use the calendar.
One month means the next calendar month
A baby born on January 15 turns one month on February 15, and two months on March 15. These intervals can contain different numbers of days. A calendar month is not a fixed four-week period.
For a January 31 birth, the first anniversary in a non-leap year is February 28. The second is March 31: every anniversary starts from the original birth date, rather than from the shortened February date.
Calendar anniversaries are not developmental deadlines
This page marks dates, not the day a baby should sit, talk or walk. CDC checklists during the first year are organized at 2, 4, 6 and 9 months, and 1 year; they do not supply an official checklist for every individual month.
Use the separate CDC resource for developmental information. If you have concerns, discuss them with your child’s healthcare professional instead of inferring development from a date result.
For babies born early
The monthly dates here count from birth. For a comparison that also counts from the expected due date, open corrected-age mode. The two starting points are always labelled separately.
Does an anniversary calendar tell me today’s age?
The calendar lists the dates on which each whole month is reached. It does not replace an age result for a comparison date between those anniversaries.
For a January 31, 2025 birth, February 28 marks one month and March 31 marks two. On March 30 the baby is still 1 month and 30 days old. Open the main calculator to choose that comparison date and see weeks and days alongside.