I usually don’t make a big deal of my birthday. But as I anticipated my 2026 birthday, the math nerd in me realized that my age will be the same as my birth year (’63) – a once in a lifetime phenomenon. The same thing is true for a child born in 2013. They turn 13 this year.
I wondered if there is a name for this occurrence. Well, there is a name for it, but it was only coined 20 years ago.
“Named after New York City firefighter Bobby Beddia, it is a fun coincidence that only occurs during even-numbered years.
The concept was born when Beddia discussed the milestone with visitor and mathematician Rhonda Roland Shearer at his fire station in 2006. Tragically, he passed away in the line of duty later that day. Afterward, mathematician Barry Cipra coined the term “Beddian Birthday” in his honor.”
I have had minutes of fun thinking about the mathematics of this doubling birthday. I’ve thought about when each of my siblings had or will have their Beddian birthday. For example, my youngest sister, Annie, will be 70 in 2040. (That’s easy math. 70 × 2 = 40). She’s seven years younger; double the difference in our ages is 14 years from now.
I thought about how some people will have to be really old, not just kind of old like me, to celebrate their Beddian birthday. A kid born in the year 2000 will have to live to be 100!
Then I read that the mathematician Barry Cipra came up with what he called the Beddia Theorem. Beddian birthdays only happen in even numbered years. Cipra determined that at any given time, you can calculate the number of ages that are pre- or post-Beddian birthdays.
• In odd-numbered years: There are exactly 50 pre-Beddian ages.
• In even-numbered years: There are exactly 49 pre-Beddian ages.
So I spent a few minutes confused, then several minutes more figuring out the time spans to prove this. I initially tried to start with 1927 and end with 2026.
1926-1963 Post-Beddian 38 ages
1964-2000 Pre-Beddian 37 ages
2001-2013 Post-Beddian 13 ages
2014-2025 Pre-Beddian 12 ages
The ages fall into two separate time spans, except for years ending in ’98, ’99, or ’00.
It works. 37+12=49
I plan to celebrate my childish enthusiasm for this silly milestone with two scoops of ice cream!
Innermost Being 