How the Half Birthday Calculator Works
A half birthday is the date exactly six months after your birthday. Enter your date of birth and the calculator gives your half-birthday date, how many days remain until the next one, and the 'and a half' age you'll be.
When the Date Doesn't Exist
Six months after 31 August isn't a real date in February (it has 28 or 29 days). In that case the calculator uses the last day of the month, so a 31 August birthday has its half birthday on 28 February, or 29 February in a leap year. The same rule applies to 30 and 31 of other months.
Why People Celebrate Half Birthdays
They're a popular treat for people with winter or holiday-season birthdays, whose real day often gets swallowed by festivities, and for children who like an extra reason for cake.
Example
A 14 March birthday has its half birthday on 14 September. A 31 August birthday has no 31 February to land on, so it's 28 February (29 in a leap year).
Frequently Asked Questions
Q: How do I find my half birthday?
A: Add six months to your date of birth. Someone born on 14 March has a half birthday on 14 September. The calculator does this for any date.
Q: What is a half birthday?
A: It's the day exactly halfway between your birthdays, six months after the last one. It's mostly a fun tradition rather than anything official.
Q: What if my birthday is on the 31st?
A: If the month six months later has fewer days, the last day of that month is used. For example, 31 August gives 28 February (29 in a leap year).
Q: What if I was born on 29 February?
A: Your half birthday is 29 August, because August has 31 days. Your leap-day birthday itself falls on 28 February or 1 March in non-leap years, depending on local convention.
Q: How old am I on my half birthday?
A: Your age plus a half. On your next half birthday you'll be shown as, for example, 26 and a half.