How to use the baby age calculator
Enter a birth date and a reference date. You will see completed calendar months, full weeks and remaining days.
How the calculation works
A calendar month is not always four weeks. This tool counts completed months using the day-of-month, with end-of-month dates clamped where needed.
Check your inputs carefully: an incorrect date can change a result. Dates and times are entered using your device settings, and no account is needed. For formal, legal, medical or financial purposes, verify the applicable local rules and official records.
Frequently asked questions
Why are months and weeks different?
A month can contain 28, 29, 30 or 31 days, while a week always contains seven days.
Does the calculator account for leap years?
Yes. AgeGlide uses calendar-based calculations and includes 29 February where applicable.
Are the dates I enter uploaded?
No. AgeGlide calculates your results in your browser. Entered dates are not sent to our server for processing.