Twenty bracelets of 6 mm rounds. How many strands?
Beads per inch is 25.4 over the bead size; the clasp eats its inch; the strand loses its rejects — beads per piece, usable per strand, strands for the batch rounded UP, and the cost per finished piece. Everything stays in your browser.
The piece
The strand
The numbers here are yours to check. This page does arithmetic on what you type — it cannot see your recipe, your equipment or your batch.
Want it to remember?
In MadeKeeper strands and findings are inventory: each piece decrements its real beads and hardware, and the price suggestion starts from what the piece truly cost to make. See for jewelry makers or poke around the live demo. $19/mo for the whole back office, kept for as long as you stay. The shop stays free for cost a piece and one fair — no product cap. The tax packet, Etsy and Square, and more fairs are the $19.
The laminated chart, live
Strand math is the difference between a shopping list and a guess: beads per piece, usable per strand, strands for the run. The math below is the same math the calculator runs.
How many beads per inch?
25.4 divided by the bead's millimeter size — 6 mm rounds run about 4.25 to the inch, 8 mm about 3.2, exactly the rows on the laminated chart every bead store hands out. The chart is right; what it cannot know is your clasp, your strand, and your rejects, which is why the calculator asks for those three and the chart doesn't.
Why deduct the clasp from the finished length?
Because an 18-inch necklace is 18 inches INCLUDING the clasp assembly — the clasp, jump rings and crimps claim three-quarters of an inch to an inch and a half depending on style, and beading the full 18 then adding hardware delivers a 19-inch necklace to a customer who ordered 18. The deduction defaults to an inch and is a setting, because a lobster claw and a three-strand box clasp are different animals.
What is the reject rate for?
The beads on a strand you will not use: off-center drills, cracks, chips, the ugly ones. Beaders plan for 5-10% on commercial strands — gemstone strands run worse than glass — so the calculator discounts each strand's count by your rate before it divides. A 16-inch strand of 6 mm nominally holds 67; at 5% rejects you plan on 63, and that four-bead difference is exactly what strands-to-buy arithmetic gets wrong on the back of an envelope.
How does the cost per piece work?
The batch buys whole strands — you cannot buy 1,440 beads, you buy 23 strands — but the piece is priced on the beads it actually uses, plus your findings. That is not a technicality: dividing the whole buy over this batch charges one necklace for beads that are still on the card, and it overstates every piece in a small run. You are right that the cash left your pocket, which is why the page shows you both numbers — what the piece cost, and what you paid for and still have. The surplus is inventory for the next batch, reported, never charged twice.