ToolPetal
Half birthday calculator
- Runs on your device
- Nothing uploaded
- Free, no sign-up
Today on your device. Change it to plan ahead.
| Upcoming half birthdays | Day | Turning | Days away |
|---|
How to find a half birthday
- Enter the date of birth. The half birthday appears at once, as a month and day.
- Read the countdown. The line under it gives the next half birthday, the weekday, the age turned and the days left.
- Plan ahead if you like. Change Count from to another date to see which half birthday comes next after it.
- Check the list. The table shows the next six half birthdays with the weekday and age.
How the half birthday is worked out
The half birthday is the same day of the month, six months after the birthday. Someone born on March 15 has a half birthday on September 15. When that day does not exist, it moves to the last day of the month: a birthday on August 31 gives a half birthday on February 28, or February 29 in a leap year. A birthday on February 29 gives August 29.
The tool also shows the exact halfway day, counting the days between one birthday and the next and splitting them in two. A year of 365 days splits into 182.5, so the true middle falls at noon, usually a day or two before or after the six month date.
Examples
| Birthday | Half birthday |
|---|---|
| January 1 | July 1 |
| March 15 | September 15 |
| June 30 | December 30 |
| August 31 | February 28 (29 in leap years) |
| December 25 | June 25 |
| February 29 | August 29 |
Why people celebrate half birthdays
Children with summer birthdays often celebrate at school on the half birthday, since the real day falls in the holidays. Holiday birthdays, like those near Christmas, get a half birthday party in June. Some families also mark a baby's first half birthday at six months.
Questions
When is my half birthday?
Your half birthday is six months after your birthday, on the same day of the month. If your birthday is March 15, your half birthday is September 15.
What if my birthday is on the 31st?
When the month six months later is shorter, the half birthday moves to its last day. August 31 gives February 28, or February 29 in a leap year, and March 31 gives September 30.
What is the half birthday for February 29?
A February 29 birthday has its half birthday on August 29 every year.
Is a half birthday exactly 182.5 days after a birthday?
Not always. The six month date can be a day or two off the exact middle, because months have different lengths. The tool shows both the six month date and the exact halfway day.
How old am I on my half birthday?
You are your age plus a half. On the half birthday after turning 7, you turn 7 and a half.
Does the tool save my date of birth?
No. The date is worked out in your browser and is not stored or sent anywhere.