What is a half birthday?

How do I calculate my half birthday?

Add six months and keep the day: January 10 becomes July 10, December 25 becomes June 25. The only trouble comes from months that run out of days.

If you want to be precise about it, count days. A year has 365, so the true halfway point is 182 and a half days after your birthday. For a January 1 birthday that lands around lunchtime on July 2. Set an alarm.

Who celebrates half birthdays?

• Babies at six months. Parents mark it with a photo, a sign with a big ½ on it, or a very small cake. By six months most babies laugh, blow raspberries, like looking at themselves in a mirror and close their lips to say they've had enough, according to the CDC's milestone list (cdc.gov/act-early/milestones/6-months.html). That's a party already.
• Kids with summer birthdays. School is out on the real day, so plenty of classrooms celebrate the half birthday instead. One San Francisco public elementary school's birthday page puts it plainly: "Students with summer birthdays get to do one of the above activities at half-birthday" (sfusd.edu/sm/node/1597). The activities include extra recess and picking a dance for the whole class to learn.
• Christmas and New Year babies. A birthday next to the holidays gets merged, rescheduled or wrapped in Christmas paper. A half birthday in June has nothing else on the calendar. For the real day, there are Christmas birthday wishes.
• Adults who want a second party. No other reason needed.

Half birthday ideas

• Half a cake. Bake a round cake, cut it down the middle and serve one half. The other half goes in the freezer for the real birthday. (It will not make it.)
• Half a song: "Happy birthday to you, happy birthday to..." and stop.
• Half a present: wrap a gift in two parts, open one now and one on the real day.
• Dessert first, then dinner. Half birthdays run backwards.
• A half day: from noon on, every choice is theirs.
• Half-and-half pizza: their favorite on one side, yours on the other.
• A halftime report: six things they did since their last birthday, read out loud at dinner.
• For summer kids at school: a non-food treat, like a book given to the class library in their name.
• For Christmas babies: the outdoor party they never get, with sprinklers instead of sleds.
• For adults: a half-marathon is allowed. A half nap is encouraged.
• Send a card on the day. A birthday card that stars them lands better when nobody saw it coming.

How to celebrate a 6 month birthday

Six months is the first birthday-shaped milestone a baby can sort of enjoy. Keep it short, at home and timed around a nap.

Take the monthly photo in the usual spot with a big ½, write a letter for the baby book about the first half, and make whoever has been doing the night feeds sit down for once.

If you want a rehearsal for the first birthday, a tiny cake does the job; here's what a smash cake is and how big to go. And six months from now: first birthday wishes and cards.

How we made the baby cards, and the candle problem

Our youngest test star is Malik, 2. Nobody in our made-up test family is six months old, so Malik works every baby shift: each first- and second-birthday idea is tried on him many times and graded on whether it still looks like him, whether it's funny, whether it fits the card and whether it's well made.

Small stars get stricter rules. Each of our kids' birthday templates says to keep the child the same age as in the photo, because babies change fast and early takes kept nudging Malik around: one cake-throne take gave him the body of a much younger baby, another made him look closer to four. Messages for toddlers have their own rule: a parent or grandparent will read it aloud, so it's simple, sweet and silly, with no sarcasm aimed at the kid.

Then there are the candles. One of the extra pictures in a birthday card is a gag called Trick Candles: the star puffs out their cheeks at candles that refuse to go out. Malik is two. Several takes gave him eight or nine candles, and the grader counted every one. On a half birthday we'd settle for half of one.

Another gag, Liftoff, floats the star up into a blue sky on far too many balloons, with the party tiny below. Malik passed that one with his feet dangling. Your message goes on the card, under the picture.