Seed bead sizes use an "aught" system where a higher number means a smaller bead — 15/0 beads are tiny (~1.5 mm diameter) while 6/0 beads are comparatively large (~4 mm). The number originally indicated how many beads fit end-to-end in one inch.
How it works
The aught notation works as follows:
- The number before "/0" is the count of beads per inch (linear density)
- Higher aught = more beads per inch = smaller bead
- 11/0 (eleven-aught) is the most popular size for beadweaving — approximately 2.1 mm diameter
Larger beads (4 mm, 6 mm, 8 mm) are sold by their actual diameter in millimeters and do not use the aught system.
Practical examples
Example 1 — Peyote stitch bracelet. Size 11/0 is standard for peyote, brick stitch, and loom work. At ~110 beads per gram, a typical bracelet uses 5–10 grams of beads.
Example 2 — Children's jewelry. Size 8/0 (~3.0 mm) is easier to work with for beginners and large enough to string easily. Good for knotted necklaces and simple bead weaving.
Example 3 — Embellishment on fabric. Size 15/0 (~1.5 mm) is used for fine embellishment work where a single bead should be barely visible — beaded lace, bead embroidery on couture garments.
Common mistakes
- Mixing brands in the same project. Toho and Miyuki 11/0s are very consistent, but Czech size 11/0s run slightly larger (~2.3 mm) and will not work interchangeably in peyote or brick stitch.
- Assuming all 11/0 beads weigh the same per gram. Delica cylinder beads (Miyuki) have a different shape than round seed beads and give a different per-gram count even at the same aught size.
- Confusing aught sizes with bugle bead lengths. Bugle beads are measured in mm length, not aught notation.
International and regional variations
| Origin | Brand examples | Consistency | Notes |
|---|---|---|---|
| Japan | Miyuki, Toho | Very high | Nearly interchangeable within the same aught number |
| Czech Republic | Preciosa, Ornela | Moderate | Slightly less uniform; may run slightly larger than Japanese equivalents |
| China | Various | Lower | Size and shape may vary more between lots |
Quick reference
| Aught size | Diameter (mm, approx.) | Best uses |
|---|---|---|
| 15/0 | ~1.5 | Fine embroidery, embellishment |
| 11/0 | ~2.1 | Most beadweaving (peyote, loom, brick) |
| 10/0 | ~2.3 | Beadweaving, slightly larger finish |
| 8/0 | ~3.0 | Stringing, knotted jewelry, beginners |
| 6/0 | ~4.0 | Statement jewelry, large embellishments |
| 4 mm | 4.0 | Stringing, focal beads |