Jewish law requires a minimum of 30 shofar blasts on each day of Rosh Hashanah.
The Torah commands a “teruah,” or ritual blast, but does not clearly define the sound’s exact form. Rabbinic interpretation identified three possibilities: tekiah-teruah-tekiah, tekiah-shevarim-tekiah, and tekiah-shevarim-teruah-tekiah. Each pattern is repeated three times.
The first two patterns contain three sounds each, while the combined shevarim-teruah pattern is counted as four. Across the three sets, that produces 30 blasts. This number is the baseline needed to fulfill the mitzvah of hearing the shofar; it is not the larger total commonly heard in synagogue services.
Many congregations follow customs of sounding 100, 101, or 102 blasts during the day. Those additional blasts are distributed around the Mussaf prayer and reflect later communal practice and differing traditions about where the sounds belong. The figures 3 and 9 refer to earlier or partial patterns, while 100 is customary rather than the minimum legal requirement.