Seed Bead Information and Sizing

Seed beads are among the most versatile and widely used beads in the crafting world. Their small size and nearly endless variety of colors, finishes, and materials make them a favorite for jewelry making, loom work, off-loom bead weaving, embroidery, crochet, knitting, embellishing garments, and countless decorative projects.

One aspect of seed beads that often confuses beginners is the sizing system. Instead of being identified primarily by their diameter in millimeters, seed beads are commonly labeled with numbers such as **6/0**, **8/0**, **11/0**, or **15/0**. This numbering system is known as the **aught system**, with the number followed by "/0" (pronounced "aught").

Although the exact origin of the aught system has been lost over time, it is generally believed to date back hundreds of years to the early bead-making industry in Europe. The traditional explanation is that the number originally represented approximately how many beads could fit side by side within a standard unit of measurement or how many beads could be produced from a particular process. Regardless of its precise beginnings, the important rule for today's beader is simple: **the larger the number before the slash, the smaller the bead.** For example, an 11/0 seed bead is smaller than an 8/0 seed bead, while a 15/0 seed bead is even smaller still.

Because seed beads are manufactured by many companies using different production methods, there is no universal standard that guarantees identical dimensions. Japanese, Czech, Chinese, and other manufacturers may produce beads with slightly different diameters, hole sizes, and overall shapes even when they share the same size designation. Specialty styles such as cylinder beads and Charlotte beads may also vary from traditional round seed beads.

The sizing information on this page is intended as a practical reference to help compare common seed bead sizes and understand their approximate dimensions. Actual measurements and bead counts may vary slightly by manufacturer, finish, and production lot, making it a good idea to verify specifications when precision is critical for a project.

Seed beads are sized using expressions such as 6/0 and 10/0. Generally, the smaller the number on the left, the larger the seed bead. Some beads are sold in hanks, which is measured a little different than yarns and other textile goods. A hank of beads is 12 strands of seed beads, folded in half and tied off. Some seed beads vary in size, color or shape from batch to batch. This variation can give your finished piece a special look of it's own. However, if you want your finished piece to be more consistent or uniform you will want to use Japanese seed beads, such as Toho beads or Miyuki Delica beads, which are the industry standard, usually sold by weight stated in grams.

The most popular thread for seed beading projects is a nylon monofilament thread, like Nymo.

Like seed beads, for needle sizes, the bigger the number, the finer the needle.