# Bar Mitzvah age- by which calendar? **URL:** \ **Category:** Factual Questions\ **Created:** [March 20, 2023, 8:54pm UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417 "2023-03-20T20:54:59Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [March 20, 2023, 8:54pm UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/1 "2023-03-20T20:54:59Z")
The age of Bar Mitzvah is now thirteen, which I don’t doubt usually now means “the same month and day of the Gregorian calendar of your birth plus thirteen years”. But if one goes by the traditional Hebrew calendar, how much different might that be? Or for that matter, was the traditional age even thirteen years or in antiquity was it measured in months? ---
**Author:** ![alphaboi867](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alphaboi867/32/3898_2.png) [@alphaboi867](https://boards.straightdope.com/u/alphaboi867)\ **Post date:** [March 20, 2023, 9:13pm UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/2 "2023-03-20T21:13:57Z")
IANAJ, but I’m sure that bar and bat mitzvah dates are always calculated according to the Hebrew calendar, not the Gregorian. ---
**Author:** ![Thing.Fish](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thing.fish/32/9168_2.png) [@Thing.Fish](https://boards.straightdope.com/u/Thing.Fish)\ **Post date:** [March 20, 2023, 9:23pm UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/3 "2023-03-20T21:23:29Z")
Correct. It would never be more than about three weeks out of sync with the solar calendar. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [March 20, 2023, 9:38pm UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/4 "2023-03-20T21:38:50Z")
Yes, bar mitzvah date is calculated on the Hebrew calendar, and it’s often celebrated at a convenient time shortly afterwards. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [March 20, 2023, 9:54pm UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/5 "2023-03-20T21:54:04Z")
Also, 13 is seen as a minimum age, it’s not required at that age, so it’s not unusual for it to be delayed a few weeks or months if that’s convenient for various reasons. ---
**Author:** ![Digital\_is\_the\_new\_Analog](https://avatars.discourse-cdn.com/v4/letter/d/a88e4f/32.png) [@Digital\_is\_the\_new\_Analog](https://boards.straightdope.com/u/Digital_is_the_new_Analog)\ **Post date:** [March 21, 2023, 12:17am UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/6 "2023-03-21T00:17:25Z")
Case in point: my bar mitzvah was about two months after my 13th birthday, because it allowed more relatives to travel easily. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [March 21, 2023, 12:41am UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/7 "2023-03-21T00:41:25Z")
Temples schedule Bar/Bat Mitzvahs over a year in advance, and the kids often get a date months away from their actual birthday. It’s nice when it’s close, but it doesn’t have to be. ---
**Author:** ![Monty](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/monty/32/47_2.png) [@Monty](https://boards.straightdope.com/u/Monty)\ **Post date:** [March 21, 2023, 1:12am UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/8 "2023-03-21T01:12:03Z")
I thought Bar/Bat Mitzvah just meant you had reached the age of majority. The ceremony is just an additional thing but is not actually required. ---
**Author:** ![Thing.Fish](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thing.fish/32/9168_2.png) [@Thing.Fish](https://boards.straightdope.com/u/Thing.Fish)\ **Post date:** [March 21, 2023, 1:19am UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/9 "2023-03-21T01:19:55Z")
Yes, that’s right. For purposes of Jewish law you become a man on your thirteenth birthday (or a woman on your twelfth). The ceremony isn’t required, so obviously it doesn’t really matter if it doesn’t happen super close to the actual birthday. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [March 21, 2023, 1:23am UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/10 "2023-03-21T01:23:53Z")
Thirteen years, or so-many (162?) months? ---
**Author:** ![Monty](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/monty/32/47_2.png) [@Monty](https://boards.straightdope.com/u/Monty)\ **Post date:** [March 21, 2023, 3:18am UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/11 "2023-03-21T03:18:34Z")
What happens if you were born in one of the intercalary months; how is your 12th or 13th birthday determined in non-leap years? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [March 21, 2023, 2:39pm UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/12 "2023-03-21T14:39:02Z")
There’s no reason to conduct the ritual on the date of one’s 13th birthday. It may happen any time after the age of 13, or not at all. It is not some kind of requirement in life like a sacrament in the Catholic church. ---
**Author:** ![hajario](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hajario/32/171_2.png) [@hajario](https://boards.straightdope.com/u/hajario)\ **Post date:** [March 21, 2023, 2:49pm UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/13 "2023-03-21T14:49:16Z")
In reform temples at the very least, the ceremony can be a short time before one’s 13th bday if that’s a convenient date. ---
**Author:** ![Thing.Fish](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thing.fish/32/9168_2.png) [@Thing.Fish](https://boards.straightdope.com/u/Thing.Fish)\ **Post date:** [March 21, 2023, 3:35pm UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/14 "2023-03-21T15:35:54Z")
Also relating to Lumpy’s question: It’s 13 years, a year being either 12 or 13 lunar months (intercalated in such a way that although each year is either 354 or 384 days, it averages out to 365 over a 19 year cycle). In leap years, there’s a second month of Adar added in the early spring. In years where there is only one Adar, your birthday is on the date of your birth no matter which Adar you were born in. So, if Abe is born on the 20th of the first Adar, and Ben is born a few weeks later on the 10th of the second Adar, Ben will reach his 13th birthday before Abe does, despite actually being younger (unless the year they turn 13 is also a leap year). ---
**Author:** ![Thing.Fish](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thing.fish/32/9168_2.png) [@Thing.Fish](https://boards.straightdope.com/u/Thing.Fish)\ **Post date:** [March 21, 2023, 3:53pm UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/15 "2023-03-21T15:53:00Z")
Right. The “ritual” really only consists of the kid reading the Torah in synagogue, which _somebody_ does at every service. Traditionally, the reason you did this for the first time near your 13th birthday was that now, by doing so, you allowed everyone else in the congregation to fulfill _their_ obligation to hear someone reading the Torah. If you had done it the week before, you would have just wasted everyone’s time and they would have had to hear an adult read it over again. As Hajario notes, Reform Jews aren’t concerned with such “obligations”, so a bit ahead of time is fine. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [March 21, 2023, 3:58pm UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/16 "2023-03-21T15:58:17Z")
Also, reform Jews celebrate both boys and girls coming of age at age 13, and both sexes read Torah for the congregation. And they may be just a bit sloppier about waiting until a girl is actually 13… ---
**Author:** ![hajario](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hajario/32/171_2.png) [@hajario](https://boards.straightdope.com/u/hajario)\ **Post date:** [March 21, 2023, 4:05pm UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/17 "2023-03-21T16:05:07Z")
Conservative Jews also have bat mitzvahs. As an aside, twins (and even friends) may have a joint ceremony and that is called a B’nai Mitzvah. ---
**Author:** ![Thing.Fish](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thing.fish/32/9168_2.png) [@Thing.Fish](https://boards.straightdope.com/u/Thing.Fish)\ **Post date:** [March 21, 2023, 4:14pm UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/18 "2023-03-21T16:14:12Z")
Yeah, I’m not sure if Conservatives observe the 12/13 distinction, but bat mitzvah for girls is standard in all non-Orthodox communities, and even many of them do something vaguely similar. (The issue is that the Orthodox hold that women, like children, can’t fulfill the obligations of others to hear Torah read in shul; so maybe they have the girl read some Torah in some non-service context, or give a speech without reading, etc.) Partially hijacked by hajario…I will note that in my very progressive shul they encourage the use of “B’nai Mitzvah” by everyone in order to include the non-binary kids. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [March 21, 2023, 4:16pm UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/19 "2023-03-21T16:16:34Z")
My temple is huge, and almost all of the kids get paired with another kid (often at random, we didn’t know the families my kids were paired with) so it’s pretty much always a b’nai mitzvah. ---
**Author:** ![ThelmaLou](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thelmalou/32/390_2.png) [@ThelmaLou](https://boards.straightdope.com/u/ThelmaLou)\ **Post date:** [March 21, 2023, 4:28pm UTC](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417/20 "2023-03-21T16:28:52Z")
In my Reform congregation there are a fair number of adults becoming bar/bat mitzvah, often but not always, adult converts. Sidebar: some people decide to go through a second bar/bat mitzvah at age 83. > **[Why Some Senior Citizens Have a Second Bar Mitzvah | My Jewish Learning](https://www.myjewishlearning.com/article/why-some-senior-citizens-have-a-second-bar-mitzvah/)** > > At his first bar mitzvah back in 1946, Harold Gorvine didn’t get to read from the Torah or give a ... > … > Not to be confused with an [adult bar/bat mitzvah](https://www.myjewishlearning.com/article/motivations-for-adult-barbat-mitzvah/), a ceremony for adults who never marked this rite of passage, the optional “second bar mitzvah” is an opportunity for older adults to reaffirm their commitment to Judaism and bring their loved ones together. > > While one can opt for this ceremony at any age, the most common age is 83. The reasoning is that it is 13 years after 70, the life expectancy described in [Psalm 90](https://www.sefaria.org/Psalms.90?lang=bi): “The span of our life is 70 years, or, given the strength, 80 years; but the best of them are trouble and sorrow. They pass by speedily, and we are in darkness.” > … > Rabbi Rachel Timoner, of Congregation Beth Elohim, a Reform synagogue in Brooklyn, N.Y., said her congregation hosted a double bar mitzvah: A longtime congregant celebrated his second bar mitzvah, at age 83, on the same day a 13-year-old member had marked his very own rite of passage. > > “It was really meaningful,” she said. “It’s a beautiful way to make intergenerational links in a community and a beautiful way to honor a person reaching the milestone of age 83.” > … [Next page](https://boards.straightdope.com/t/bar-mitzvah-age-by-which-calendar/981417.md?page=2)