According to the Kitzur Shulchan Aruch (6:7), “חַיָּב אָדָם לְבָרֵךְ בְּכָל יוֹם מֵאָה בְרָכוֹת לְפָחוֹת” At minimum, one is required to recite “Meah Brachos”, 100 Blessings, every day, as instituted by David HaMelech. A hint to this effect is found in Shmuel II (23:1) “וּנְאֻם הַגֶּבֶר הֻקַם עָל”. The Gematria of the word עַל is one hundred. The Baal HaTurim in Shemos (38:27) writes that the institution of reciting 100 Brachos each day corresponds to the 100 sockets of the Mishkan.
On Shabbos, Yom Tov and on fast days which lack the hundred Brachos, since the Shemoneh Esrei on Shabbos and Yom Tov is much shorter, the usual number of Brachos are not recited. Similarly on fast days when we do not eat or say Birchas Hamazon, the usual number of Brachos are not recited. We compensate by concentrating on the Brachos recited by the Chazzan when he repeats the Shemoneh Esrei, and on the Brachos recited over the Torah reading and the reading of Maftir, after which we answer Amen. Similarly Brachos over foods add to the total.
To help you keep track of your 100 Brachos a day, we have created a free printable checklist. Download it, print it and share it with your friends!