The standard sizes for Mala beads used for Mala necklaces are 6 and 8 millimeters. 

While Mala bracelets can be made with 10- and 12-millimeter beads, doing so will make it extremely difficult for meditation. Mala beads should always be in proportion to the size of your fingers and the agility of your hands which is the best determining factor for acquiring the best bead size. For a wrist or bracelet, the circumference should always be one half inch larger that the size of your wrist.

Generally, a Mala necklace is made of 108 beads in all faiths except the Muslim faith which uses 106, with the main bead known as a Guru resting on the center of your chest. As well, Malas can consist of 54, 27, 21 or 19 Mala beads.