Yarn Calculator
Estimate how much yarn a knitting or crochet project needs — yards, meters, grams and skeins — from the project type, yarn weight and stitch pattern, with a built-in safety buffer.
Input
Typical yardage for a medium adult size, worsted weight, stockinette.
Check your yarn's label — this varies a lot by brand and weight.
Output
| Metric | Value |
|---|---|
| No data yet | |
Guides
The Yarn Calculator estimates how much yarn a knitting or crochet project needs — in yards, meters, grams and skeins — from the project type, yarn weight and stitch pattern. It's a planning estimate for figuring out how much to buy before you start, not a substitute for a pattern's own stated requirements.
It runs entirely in your browser: no account, no uploads, nothing leaves your device.
How the estimate works
- Base yardage — a typical yardage for a medium adult size, worsted (medium) weight yarn, plain stockinette stitch, for the project you pick (sweater, blanket, scarf, hat, socks…). Have a pattern's own stated yardage instead? Pick Custom and enter it directly.
- Yarn weight adjustment — thinner yarn is worked at a tighter gauge and needs more length to cover the same area; thicker yarn needs less. Choosing a weight other than Medium scales the base yardage up or down accordingly.
- Stitch pattern adjustment — cables, ribbing, colorwork and brioche all use noticeably more yarn per square inch than plain stockinette; open lace stitches typically use a little less.
- Safety buffer — a fixed 10% is added on top, the standard cushion for gauge swatches, seaming, and simply not running short a few rows from the end.
The total is then converted to meters and grams, and divided by your yarn's yards per skein (check the label — this varies a lot by brand and weight) to get how many skeins to buy, both rounded up and as an exact count.
How to use it
- Pick your Project — or Custom to type in a base yardage from your own pattern.
- Pick the Yarn weight and Stitch pattern you're working with.
- Enter Yards per skein from your yarn's label (200 is a common worsted-weight default).
- Read the result line and the full breakdown table — copy the result or download the breakdown as CSV.
Why these numbers are estimates, not guarantees
Every knitter's gauge, tension and exact size varies, and patterns differ in how much ease, edging, or colorwork they use even within one category. Treat this as a starting shopping list — buying one extra skein beyond what it suggests is cheap insurance against dye-lot mismatches and running short, and is far easier than hunting down one more skein of a discontinued colorway mid-project. Always defer to a specific pattern's own stated yardage when you have one.
Use it from code
From 3 credits per callREST API
curl -X POST https://api.iotools.cloud/v1/tool/yarn-calculator \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"projectType": "sweater_m",
"yarnWeight": "medium",
"stitchPattern": "stockinette",
"skeinYards": "200"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `yarn-calculator` tool (Yarn Calculator) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.