At what age is a bar mitzvah?

At 13 by the Hebrew calendar – on the Hebrew date of birth thirteen years later.

Does a boy need a ceremony to become bar mitzvah?

No. He becomes obligated in the mitzvot automatically at 13; the ceremony celebrates it.

What does bar mitzvah mean?

Literally “son of the commandment” – a person subject to the commandments.

What gift is customary?

Common gifts are Jewish books, a tallit, money (often in multiples of 18) or something meaningful to the boy.

Bar mitzvah – what it is and how it is celebrated בַּר מִצְוָה

A Jewish boy becomes bar mitzvah – “subject to the commandments” – at 13 by the Hebrew calendar. From that day he is responsible for keeping the mitzvot, counts in a minyan and may be called to the Torah. The celebration marks the change; the obligation comes automatically with age.

The source

The Mishnah teaches “at thirteen, for the commandments” (Avot 5:21). The Midrash connects the verse “and the boys grew up” (Genesis 25:27) – Jacob and Esau going their separate ways at thirteen – with the blessing a father says on that day: “Baruch shepetarani me’onsho shel zeh” – blessed is He who has released me from responsibility for this one (Bereshit Rabbah 63:10; Rema, Orach Chayim 225:2).

How it is celebrated

Putting on tefillin for the first time (many begin a month or so before).
An aliyah to the Torah, often reading the weekly portion or the haftarah, on a Monday, Thursday or Shabbat.
A short Torah talk (derashah) by the boy.
A festive meal, considered a seudat mitzvah by many authorities.

Sephardi and Ashkenazi customs

Ashkenazim usually celebrate on Shabbat, with the boy reading the portion and haftarah. In many Sephardi, especially North African, communities the highlight is a weekday morning with the first tefillin, songs and sweets, while the aliyah follows on Monday, Thursday or Shabbat. The Hebrew birthday decides the date, so the bar mitzvah may fall on a different secular date than the birthday.

Sources

וַיִּגְדְּלוּ הַנְּעָרִים וַיְהִי עֵשָׂו אִישׁ יֹדֵעַ צַיִד אִישׁ שָׂדֶה וְיַעֲקֹב אִישׁ תָּם יֹשֵׁב אֹהָלִים
Genesis 25:27

Talmud and halachic sources

Mishnah, Avot 5:21
Bereshit Rabbah 63:10
Shulchan Aruch, Orach Chayim 225:2 (Rema); 37:3 (tefillin)

Frequently asked questions

At what age is a bar mitzvah?: At 13 by the Hebrew calendar – on the Hebrew date of birth thirteen years later.
Does a boy need a ceremony to become bar mitzvah?: No. He becomes obligated in the mitzvot automatically at 13; the ceremony celebrates it.
What does bar mitzvah mean?: Literally “son of the commandment” – a person subject to the commandments.
What gift is customary?: Common gifts are Jewish books, a tallit, money (often in multiples of 18) or something meaningful to the boy.