Knitting Needle Size Converter
Convert knitting needle sizes between US, metric (mm) and UK/Canadian numbering. Enter one size and see its equivalents, plus the full needle size chart.
Input
UK/Canadian sizes run from 14 (thinnest) down to 000. Metric accepts any value; the nearest chart size is used.
Output
| System | Size |
|---|---|
| No data yet | |
| US | Metric | UK / Canadian |
|---|---|---|
| No data yet | ||
More ways to use this tool
REST API
curl -X POST https://api.iotools.cloud/v1/tool/knitting-needle-size-converter \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"system": "us",
"size": "8"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `knitting-needle-size-converter` tool (Knitting Needle Size Converter) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.
Embed widget
<iframe
src="https://iotools.cloud/embed/knitting-needle-size-converter/"
width="100%" height="520" frameborder="0" scrolling="no" loading="lazy"
title="Knitting Needle Size Converter — iotools.cloud"
sandbox="allow-scripts allow-forms allow-same-origin allow-downloads allow-popups allow-popups-to-escape-sandbox"
allow="clipboard-write"
style="width:100%;border:1px solid #e5e7eb;border-radius:12px;overflow:hidden"></iframe>
<script src="https://iotools.cloud/embed.js" async></script>Drop this into your own page — free, no key required, just a link back.
| Cost per API/MCP call | From 5 credits |
|---|---|
| Need more credits? | View pricing |
Also available with
Guides
Knitting needles are sold under three different sizing systems: US numbers, metric millimetres and the old UK/Canadian numbers. A pattern written for one is awkward to follow with needles labelled in another. This converter turns any one size into the other two and shows the whole chart.
How to use it
- Pick the system you are converting from: US, metric or UK/Canadian.
- Type the needle size, such as
8,5.0or000. - Read the equivalent sizes and the full chart below.
How the systems differ
- Metric is the diameter of the needle in millimetres. It is the only system that measures the same thing everywhere, so it is the safest to compare.
- US sizes are numbered from 0 (2 mm) up to 50 (25 mm), with half sizes such as 1.5 and 10.5.
- UK/Canadian sizes count backwards: 14 is the thinnest (2 mm) and 000 is 10 mm.
Sizes without an equivalent
Some needles only exist in one system. For example, 3.5 mm is US 4 but has no UK/Canadian number, and UK 2 (7 mm) has no standard US size. Those cells show a dash. If you enter a metric size that is not on the chart, the nearest chart size is used and the result says so.
Tips
- Always knit a gauge swatch. Needle size is a starting point; your tension decides the final fabric.
- Brands round differently, so a "US 6" can differ slightly. Check the mm marking on the needle when in doubt.
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