Knitting Needle Size Converter — US, UK & Metric

Convert knitting needle sizes between US, UK and metric (mm).

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Knitting Needle Size Converter

Craft • US/UK/mm

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Choose a size to see equivalents

How to Use the Knitting Needle Size Converter

  1. Pick the system you know — choose the sizing standard you already have (e.g. US).
  2. Select your size — pick your known size from the list.
  3. Read every equivalent — all other systems update instantly, with your source highlighted.

Why Use This Knitting Needle Size Converter

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Accurate Standards

Built on internationally recognised SI and standards-body conversion factors for dependable results.

Instant & Animated

Results update live as you type, with a clear visual breakdown across every unit at once.

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100% Private

Everything runs in your browser — no account, no uploads, nothing leaves your device.

Understanding the Knitting Needle Size Converter

Knitting needles are sized differently in the US, the UK and metric (mm), and the old UK scale runs backwards. This chart converts needle sizes across all three systems so you can follow any pattern.

Knitters working from international or vintage patterns use it to match the gauge a pattern calls for. The metric (mm) value is the unambiguous one to rely on when in doubt.

Knitting Needle Size Converter FAQ

Largely yes — UK/old sizes get smaller as the needle gets thicker, while US sizes get larger. Always check the mm value, which is unambiguous.

Related Converters

✔ Reviewed by the True Value Calc editorial team🗓 Last updated June 2026📚 Sources: NIST, BIPM SI unit definitions