How to use the bead strand calculator
- Pick the unit and enter the finished length of the strand, measured on the beaded part.
- Enter the bead size in millimeters along the thread.
- Open More options to add space between beads, length taken by the clasp and crimps, and a spare share for breakage.
- Read the beads needed, the count if rounded down, and the length your strand will come to.
Formula
usable length = strand length in mm - clasp allowance
beads = usable length / (bead size + space between beads), rounded up
with spares, beads to buy = beads x (1 + spare / 100), rounded up
There are 25.4 millimeters in an inch and 10 in a centimeter. The count is rounded up so the strand reaches full length, and the rounded-down count is shown for a slightly shorter strand.
A 16 inch necklace of 6 mm beads
Sixteen inches is 16 x 25.4 = 406.4 mm. Dividing by 6 mm per bead gives 67.73, so you need 68 beads, or 67 for a strand a little under 16 inches.
With 8 mm beads, 1 mm of space between each and a 30 mm clasp allowance, the usable length is 376.4 mm and each bead takes 9 mm, so 376.4 / 9 = 41.8 and you need 42 beads. A 40 cm strand of 6 mm beads needs 67, and 10 percent spare buys 74.
Why you should lay the beads out
Beads are never perfectly uniform, and round beads sit slightly differently on a thread than square ones. Thread and cord also stretch or sag a little. A bead board with a measured channel lets you lay beads out and compare with the count here before you string them.
Bead size is the width along the thread. For beads with different sizes, such as a large focal bead among small ones, work out each size section separately and add the counts.
More craft planning
See the Crochet Chain Calculator, the Cross Stitch Size Calculator or the Weaving Warp Calculator. The Unit Converter switches between millimeters and inches.
Assumptions and limits
- Every bead is the same size along the thread.
- The space between beads is the same everywhere.
- Bead hole size, knots, drape and stretch are not modeled.
- The clasp allowance is taken off the strand length first.
Frequently asked questions
How many beads do I need for a 16 inch necklace?
With 6 mm beads, 68. A 16 inch strand is 406.4 mm and each bead takes 6 mm, so 406.4 divided by 6 is 67.7, which rounds up.
How do I count beads for a bracelet?
Use the finished length of the beaded part, subtract the clasp, and divide by the bead size. A 7 inch bracelet of 6 mm beads needs about 30.
Should I include the clasp in the length?
Enter the length of the beaded part only, or use the clasp allowance to remove the clasp from the total.
How many spare beads should I buy?
Many makers buy a few extra for chips and test layouts. Enter a spare share in More options to see the count.