Seed Beads: A Guide for Buyers & Sellers

"Seed" beads are not actually seeds, but rather they are tiny glass beads ranging in size from about 6° (about 3/16") to the nearly microscopic vintage 22° (The higher the number, the smaller the bead).

Historically, sizes 5° - also known as E beads - and 6° have been referred to as pony beads, and crow beads are even larger than that. Nowadays, perhaps because the Japanese tend to manufacture coordinated colors in sizes all the way up to 2°, many sellers just refer to them all as seed beads.

Seed beads have been and continue to be manufactured in many countries, but in the U.S. today we import our best quality seeds from Japan and the Czech Republic. For now, I'll limit my discussion to these two countries.

Seed beads are used in bead embroidery, loomwork, stringing, and a wide range of beadwork stitches, including crochet and macrame, as well as crazy quilts, fiber arts, jewelry and other artful craft applications.

The smaller the bead, the smaller the needle needs to be, and therefore, the smaller the eye in that pesky little needle, and the more challenging the beads are to work with! Size 11°s are the most common size for beadwork projects, followed by Delicas, which are preferred for closely woven stitches.

In this guide, the degree symbol (°) stands for 'aught,' a term of dubious and debatable origins in beadland. Aught means zero and it refers to how many of the little buggers will fit into a 'standard unit of measure.' In other words, if 11 of them will fit, we say the beads are size 11° (eleven aught).
Some people say the standard unit of measure is an inch, but I doubt it, for two obvious reasons: 1) you can fit more than 11 size 11°s in an inch, and 2) they don't use inches much in Europe, where the term came into usage.
Ah well, whatever the 'standard unit of measure' might have been (the Czech beadmaker's pinky finger?), understanding the term in general does help to explain why smaller beads get a higher number. In other words, 13° seed beads are smaller than 11° seed beads.