Bead Quantity Calculator
When beads are strung hole to hole, the number that fits a length is simply that length divided by the bead size. Enter your strand length in inches, the bead diameter in millimetres, the number of strands and a waste allowance, and this tool returns the beads per strand and the total beads to buy.
Bead quantity formula
Strand length (mm) = strand length (in) * 25.4
Beads per strand = floor(strand length mm / bead diameter mm)
Base beads = beads per strand * number of strands
Total to buy = ceil(base beads * (1 + waste / 100))
One inch is exactly 25.4 mm. Beads per strand uses floor since a partial bead does not fit; the waste allowance then pads for losses.
Worked example
A 16 inch strand is 16 times 25.4 = 406.4 mm. With 6 mm beads, beads per strand = floor(406.4 / 6) = floor(67.7) = 67. Across 3 strands that is 201 beads. With a 10 percent waste allowance, total to buy = ceil(201 times 1.10) = ceil(221.1) = 222 beads.
Bead quantity: frequently asked questions
How many beads fit in a given length?
When beads sit hole to hole along a thread, the count is the strung length divided by the bead diameter. For example a 16 inch (406.4 mm) strand of 6 mm round beads holds about 406.4 divided by 6, which is about 67 beads.
How do I count beads for a whole project?
Multiply the beads per strand by the number of strands, then add a waste allowance for breakage, mistakes and sizing. A small percentage buffer (the field is editable) helps avoid running short of a specific colour or finish.
Does bead shape change the count?
Yes. The hole-to-hole count assumes the bead's length along the thread equals the diameter you enter. For non-round beads, enter the dimension that lies along the stringing direction rather than the widest measurement.
How do I convert inches to millimetres for bead sizing?
Bead sizes are usually given in millimetres while strand lengths are often in inches. One inch is 25.4 mm. This calculator lets you enter the length in inches and the bead size in millimetres and handles the conversion.
Sources and notes
- The bead count is geometry: hole-to-hole beads number the strung length divided by bead diameter. The inch-to-millimetre factor of 25.4 is exact by definition.
- Bead size and strand length are your project values; this tool assumes no fixed bead.
Reviewed by the CalculatorHub team, edited by James Graham, 19 June 2026. See our methodology.