4. What do the numerical sizes on seed beads mean? Are they consistent among all seed beads?
The numerical sizes on seed beads are useful for comparing relative seed bead sizes. The larger the bead, the smaller the number – for example, 8º seed beads are larger than 15º beads. What makes this tricky is that different manufacturers may use different standards for measuring the beads they make. Czech glass seed bead sizes were originally termed “aught” (identified by the symbol °). The term "aught" referred to how many beads could fit into a standard unit. In recent years, the Japanese have begun producing seed beads with greater accuracy, and the “aught” system is no longer applicable. The term aught, however, remains. In general, 11º Czech seed beads are slightly smaller than 11º Japanese seed beads. Sizing among Japanese seed beads is more consistent than sizing among Czech seed beads, but even among Japanese seed bead manufacturers, beads with the same numerical designation may differ slightly in size. If consistency is important to your design, you may want to consider using Delica brand seed beads. Delica beads are cylindrical seed beads that are beautifully consistent in size and shape.