Seed bead size chart (mm)
Seed beads use the "aught" system — the bigger the number, the smaller the bead. Millimeter sizes are approximate and vary by brand, so each size below is shown as a range with Miyuki / Toho / Czech notes.
Seed bead sizes
| Aught size | Diameter (mm) | Approx beads / inch | Typical use |
|---|---|---|---|
| 6/0 | 4–4.3 mm | 6–6 | Beaded knitting, kids' crafts, fringe, and larger embellishment. |
| 8/0 | 2.5–3.1 mm | 8–10 | All-purpose beadweaving, bead crochet, and edging. |
| 10/0 | 2–2.3 mm | 11–13 | A middle size between 8/0 and 11/0; common in older Czech patterns. |
| 11/0 | 1.8–2.1 mm | 12–14 | The default for peyote, brick, and most beadweaving patterns. |
| 15/0 | 1.3–1.4 mm | 18–20 | Detail rows, tight finishing, and sharp decreases. |
Seed bead sizes at actual size
Each circle uses the midpoint of that aught size's millimeter range. Calibrate or print so they are physically accurate.
Printed at 100% scale, the marks below should measure exactly: the gold line = 1 inch, the "50" tick = 50 mm. If not, set your print scale to 100% (not "fit to page").
How many seed beads per length?
Counts use the midpoint mm of each aught size and the 25.4/mm rule — treat them as estimates and add ~10% for tension and finishing.
Brand & type notes
- 6/0: Sometimes called 'E beads.' Japanese (Miyuki/Toho) run near the top of this range; Czech 6/0 can be a touch smaller.
- 8/0: Miyuki and Toho 8/0 are about 3.0 mm; Czech 8/0 tend to be slightly smaller.
- 10/0: Less common in Japanese lines; mostly seen as Czech 10/0.
- 11/0: The most common beadweaving size. Miyuki/Toho 11/0 round are about 2.0 mm; Czech 11/0 are closer to 1.8 mm; Miyuki Delica 11/0 (cylinder) is about 1.6 mm.
- 15/0: Miyuki/Toho 15/0 are about 1.5 mm in practice; Charlottes are smaller still.
Sources, calibration & how the counts are computed
On-screen sizes are only accurate after you calibrate your display to a real credit/debit card (ISO/IEC 7810 ID-1 = 85.60 mm wide). Before you calibrate, beads are shown NOT to scale. For a guaranteed-accurate size, use the print view at 100% with the printed ruler.
Beads per inch and beads per strand use the standard estimate beads = round(length_in x 25.4 / diameter_mm), where 1 inch = 25.4 mm. Counts are approximate; actual bead lots vary.
Data basis: Seed-bead aught-to-millimeter ranges from the Wikipedia seed-bead standards table (explicitly approximate and brand-varying), with Miyuki/Toho/Czech specifics from spoiltrottenbeads.co.uk and beads.co.
Last reviewed 2026-06-18.
General jewelry-making reference. Bead dimensions are approximate and vary by manufacturer, material, and finish; measure your own beads with calipers when precision matters.