mm to US knitting needle size
Type your needle diameter in millimeters to find its number in American patterns.
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How to use it
- Enter needle diameter.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
The diameter is looked up in the Craft Yarn Council chart; if there is no exact match, the closest size and the difference in mm are shown.
Example
Inputs: Needle diameter = 4 mm. Result: US size: 6; Diameter of that size: 4 mm; Exact match: Yes.
Limits and caveats
- The chart used does not list sizes such as 3 or 7 mm, so the nearest US size is shown for them.
- If the diameter falls exactly midway, the smaller size is shown.
Questions about this tool
What US size is a 4 mm needle?
US 6.
What US size is a 5 mm needle?
US 8.
What if there is no exact match?
Use the nearest size and knit a swatch, then change needles if your stitch count differs from the pattern.