Beading Pattern Calculator
Calculate how many beads you need from a strand length and a repeating bead pattern, with a per-bead-type shopping list, editable waste/overage allowance, and results for multiple strands at once — free, no signup, runs entirely in your browser.
Input
Sets the unit for strand length and clasp length. Bead sizes are always entered in millimeters.
The clasp's own length, in the unit selected above — subtracted from the strand length to get the length actually available for beads. Common clasps run 0.5–1 in (12–25 mm).
How many identical strands to make — the shopping-list totals multiply by this.
Extra beads to buy for breakage, knotting mistakes, and picking the best-matched beads.
One bead type per line, in the order they're strung within one repeat, as "Name | Size (mm) | Count per repeat". Name is optional.
Output
| Metric | Value |
|---|---|
| No data yet | |
| Bead | Size | Per Repeat | Per Strand | Total To Buy |
|---|---|---|---|---|
| No data yet | ||||
Guides
What does this calculator do?
The Beading Pattern Calculator turns a finished strand length and a repeating bead pattern into an exact, per-bead-type shopping list. Give it your strand length, clasp size, and the sequence of beads that repeats along the strand (say, "3 red seed beads, then 1 blue accent bead"), and it tells you how many of each bead type you need — plus a buffer for breakage and mistakes.
How the numbers are worked out:
- Usable length:
strand length − clasp length— the length actually available for stringing beads. - Repeat length: the total length of one pass through your pattern, adding up each bead type's size times its count in the repeat.
- Full repeats:
usable length ÷ repeat length, rounded down. - Leftover space: whatever's left after the full repeats is filled bead-by-bead, in the same order they're strung, until no more beads fit — the same way a beader actually finishes off a strand, rather than stopping at the last complete repeat.
- Waste/overage: a percentage added on top of the raw bead count, per bead type, to cover breakage, re-stringing, and picking the best-matched beads from a batch.
- Multiple strands: the whole calculation multiplies out by how many identical strands you're making.
Worked example: an 18in strand with a 0.75in clasp leaves 438.1mm to fill. A "3 red (4mm) + 1 blue (6mm)" repeat is 18mm long, so it fits 24 full repeats (432mm) plus one more red bead in the 2.1mm left over — 97 beads per strand, or 102 with a 5% waste allowance.
How to use it
- Enter the finished strand length and pick inches or centimeters.
- Enter the clasp length in the same unit — this gets subtracted from the strand length automatically.
- Set the number of strands if you're making more than one.
- Set a waste/overage percentage — 5–10% is typical for seed beading.
- Enter your bead pattern, one bead type per line, in the order they're strung within one repeat:
Name | Size in mm | Count per repeat. The name is optional — leave it off and the tool labels beads "Bead 1", "Bead 2", and so on.
The Strand Results table shows the overall totals, and the Beads to Buy table breaks the shopping list down by bead type — both are copyable and downloadable as CSV.
Why does bead size need to be in millimeters?
Bead sizes (2mm, 4mm, 6mm seed beads, 8mm rounds, and so on) are conventionally sold and measured in millimeters regardless of what unit you're using for the strand itself, so the pattern line always expects millimeters even if you picked inches for the strand length.
What if my pattern doesn't divide evenly into the strand?
It almost never will — that's normal. The calculator fills the leftover space with as many more beads from the front of the pattern as still fit, then reports the small amount of space left over (too small to fit another bead) so you know exactly how the strand ends.
Privacy
This calculator runs entirely in your browser. Your measurements and bead pattern are never sent to a server, logged, or stored — the math happens locally on your device.
Use it from code
From 3 credits per callREST API
curl -X POST https://api.iotools.cloud/v1/tool/beading-pattern-calculator \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"strandLength": "18",
"lengthUnit": "in",
"claspLength": "0.75",
"pieces": "1",
"wastePercent": "5",
"pattern": "Red seed bead | 4 | 3\nBlue accent bead | 6 | 1"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `beading-pattern-calculator` tool (Beading Pattern Calculator) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.