About the Bead Calculator
This bead calculator tells you how many beads you need to string a bracelet, anklet or necklace of a given length. Enter the finished length you want, the bead size in millimetres, any gap or spacer between beads and the length taken up by the clasp, and it returns the bead count per strand, beads per inch and the cost for your whole design.
It is useful when buying beads online by the strand, planning a multi-strand piece, or working out whether a 15 in (38 cm) strand of beads is enough for a necklace. A table shows the bead count for the standard jewellery lengths — bracelet, anklet, choker, princess, matinee and opera — at the same bead size.
Round beads are measured by diameter, so a 6 mm bead takes 6 mm of stringing length. For rondelles and other shapes, enter the length along the hole. The count is rounded to the nearest whole bead, so the finished length shown may differ from your target by up to half a bead.
With the default inputs, the beads needed is 28 beads. Change any value above to recalculate instantly.
How to use the bead calculator
- 1Choose inches or centimetres and enter the finished length, including the clasp.
- 2Enter the bead size in millimetres (diameter for round beads).
- 3Add a spacer or knot size if beads will not touch, and the clasp length.
- 4Set the number of strands and the price per bead.
- 5Read the bead count and check the table for other standard lengths.
Formula and method
The finished length is converted to millimetres (25.4 mm per inch) and the clasp and findings are subtracted to give the length available for beads. With n beads and a spacer or gap between each pair there are n beads and n − 1 gaps, so n × size + (n − 1) × gap must equal the available length, which rearranges to n = (available + gap) ÷ (size + gap).
The result is rounded to the nearest whole bead, and the actual finished length is recalculated from that whole number so you can see how close it is to your target. Multiply by the number of strands for multi-strand designs; the cost is the bead count times your price per bead.
- Length
- Desired finished length in mm, including clasp
- Clasp
- Length of clasp, jump rings and crimps in mm
- Gap
- Spacer bead or knot length between beads in mm
Worked examples
7 in bracelet with 6 mm beads
Seven inches is 177.8 mm; removing a 10 mm clasp leaves 167.8 mm. 167.8 ÷ 6 = 27.97, which rounds to 28 beads, finishing at 28 × 6 + 10 = 178 mm (7.01 in). At $0.15 each the beads cost $4.20.
18 in necklace of 8 mm beads with 3 mm spacers
18 in is 457.2 mm; minus a 12 mm clasp leaves 445.2 mm. (445.2 + 3) ÷ 11 = 40.75, so 41 beads with 40 spacers, which measure 41 × 8 + 40 × 3 + 12 = 460 mm (18.11 in). 41 beads at $0.25 cost $10.25.
Three-strand 19 cm bracelet of 4 mm beads
19 cm is 190 mm; minus 8 mm of clasp leaves 182 mm, or 45.5 beads of 4 mm, rounded to 46. Three strands need 138 beads, and each strand finishes at 46 × 4 + 8 = 192 mm (19.2 cm).
Frequently asked questions
How many beads do I need for a bracelet?+
For a 7 in (17.8 cm) bracelet you need about 42 beads of 4 mm, 34 of 5 mm, 28 of 6 mm, 21 of 8 mm or 17 of 10 mm, allowing about 10 mm for the clasp. Adjust the length to the wrist plus 1/2–1 in for comfort.
How many beads are in an inch?+
Divide 25.4 by the bead size in millimetres. That gives about 6.35 beads per inch for 4 mm beads, 4.23 for 6 mm, 3.18 for 8 mm and 2.54 for 10 mm, when the beads sit touching with no spacers.
How many beads are on a 15 inch strand?+
A 15 in strand is 381 mm long, so it holds about 95 beads of 4 mm, 63 of 6 mm, 47 of 8 mm or 38 of 10 mm. Actual counts vary slightly because bead sizes are nominal.
What are standard necklace lengths?+
Common lengths are choker 14–16 in, princess 17–19 in, matinee 20–24 in, opera 28–34 in and rope 36 in or longer. Bracelets are usually 6.5–8 in and anklets 9–11 in.
How do I measure bead size?+
Beads are sold by size in millimetres measured across the widest point. For round beads that is the diameter; for rondelles, tubes and other shapes, measure the length along the hole, because that is the space it takes on the string.