A Useful Overview of Seed Bead Sizes

Confused about seed bead sizes? Well, here’s a handy guide explaining what they mean.

Seed beads, also known as rocailles, are uniformly shaped beads that vary in size from less than a millimeter to several millimeters. They are typically made of glass, but there are metal seed beads too.

Seed beads are usually rounded in shape but the term is used as a generic name for any small bead. Multiple manufacturers produce various shapes and there are tons of different seed bead finishes available.

These tiny beads are very commonly used in off-loom bead weaving and it’s important to use the correct size for a beading project. In this post, I’ll discuss the most popular sizes of seed beads on the market.

A Guide To Seed Bead Sizes

Seed Bead Sizes Unit of Measurement

Aught is the unit of measurement given to round seed beads, cylinder beads and other types of seed beads. It’s represented in a few different ways:

• A number, followed by a degree symbol (°)
• A number, followed by a slash and a zero (/0)
• Or simply the word “size” and a number

The most common seed bead sizes are 6/0, 8/0, 11/0 and 15/0. Each of these sizes could be denoted in one of the other ways. For example, 6/0 could also be written as 6° or size 6.

What Does Aught Size Really Mean?

There is no real guidance as to how the seed bead sizes were originally determined. However, it is thought that aught size referred to the number of beads that could be lined up side-by-side, with their holes facing upward, within an inch of space.

For this reason, the larger the number of seed beads that could fit into one inch, the smaller the beads were. Therefore, a 6/0 seed bead is larger than a 15/0. Many new beaders find this quite confusing.

Are Seed Bead Sizes Consistent?

Seed bead sizes have changed over the years with the invention of new manufacturing techniques, as well as production by different companies. As a result, the aught system no longer applies but the term is still used today.

The shape of the seed bead also affects the size of it. Miyuki Delica beads are more slender that the rounded seed beads. Czech seed beads tend to be rounder than Toho seed beads.

When working on a beading project, you definitely need to be aware of what the design requires. If consistency in shape and size is important, stick to one brand of seed bead. Japanese seed beads are usually more uniform.

If you want a more organic look and feel, you can mix up the brands.

Do All Seed Beads Use Aught Sizing?

As I mentioned before, seed beads come in various shapes. Not all of these use aught sizing. Fringe or drop beads and bugle beads are considered seed beads but these are measured in millimeters.

Most beading patterns list the bead sizes you’ll need and, in some cases, also specify a particular seed bead brand. If you want to replicate the design exactly as is shown, you’ll need to use the same materials since sizes vary according to the type of bead and the manufacturer.