How to use the half birthday calculator
Enter your date of birth. The calculator adds six calendar months to the yearly birthday and finds the next upcoming half-birthday date.
How the calculation works
Six calendar months is not always 182 or 183 days. Dates such as the 31st are adjusted to the last valid date when 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
Do half birthdays happen exactly 182 days later?
Not always. This tool uses six calendar months instead of a fixed day count.
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.