At what age is a bar mitzvah and a bat mitzvah?

The ages

Pirkei Avot says: “At thirteen, for the commandments.” The Mishnah sets twelve for girls, who mature earlier. The day is the Hebrew birthday: a boy born on 10 Cheshvan becomes bar mitzvah on 10 Cheshvan thirteen years later, from the evening before.

What changes

A bar mitzvah boy counts in a minyan, puts on tefillin every weekday, can be called up to the Torah and is responsible for his actions. A bat mitzvah girl is obligated in the commandments that apply to women. Parents traditionally say a blessing (“Baruch shepetarani”) when the son becomes bar mitzvah.

Celebrations

Boys are called up to the Torah, often reading the portion and Haftarah, and give a talk on Torah. Bat mitzvah celebrations vary by community, from a festive meal with a talk to, in egalitarian communities, reading from the Torah. A seudat mitzvah – festive meal – is customary.

Sephardi and Ashkenazi customs

Sephardi boys often begin to put on tefillin a month or more before the bar mitzvah; many Ashkenazim begin about a month before, some two or three months. In many Sephardi communities the bar mitzvah boy is called up on a Monday or Thursday to put on tefillin in the synagogue, with a celebration following.

The age of a child born in Adar

A boy born in Adar of a regular year becomes bar mitzvah in Adar II if his thirteenth year is a leap year; one born in Adar I or II of a leap year celebrates in the matching Adar if his thirteenth year is also a leap year, otherwise simply in Adar. Our Jewish calendar helps to find the Hebrew date.