Bead Count Calculator
Find how many beads fill a given length from their size, and how many you need for a whole strand or project with a spare margin.
How it works
Length (mm) = inches × 25.4 · Beads per strand = floor(length ÷ bead size) · Total = per strand × strands · Buy = ceil(total × (1 + spare))
Round beads sit one diameter apart along a strand, so the number that fills a length is simply the length divided by the bead's diameter. Converting inches to millimetres lets you use the bead size printed on the tube (bead sizes are almost always in mm). A spare margin matters because beads vary slightly in size, some have flaws you discard, and a broken strand needs a few extras to repair — running out of a dye lot mid-project can be impossible to match. Multiply by the number of strands or pattern repeats for the full purchase.
Worked example
An 18 in strand of 6 mm beads: 18 × 25.4 = 457.2 mm, divided by 6 gives 76 beads per strand. For one strand with a 10% spare margin you buy ceil(76 × 1.1) = 84 beads.
Frequently asked questions
Do bead sizes match their labels?
Roughly. Round beads are close to their stated mm diameter, but seed beads use an "aught" system (11/0, 8/0) where a higher number is smaller — convert to mm first. Shaped beads pack differently, so measure the dimension that lies along the strand.
Why buy spares?
Beads vary in size, a few per batch are misshapen or have blocked holes, and repairs need extras. A 10–15% margin means you are not hunting for a matching dye lot later.
How do I count beads for a woven pattern?
Multiply beads per row by the number of rows, or use the strands field for repeats. For gap spacers between beads, subtract the spacer length from the strand before dividing.
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This calculator is for educational purposes. Double-check important results before acting on them.