Yarn & Needlecraft
What Size Knitting Needle Do I Have?
Put the straight part of the needle against the gauge and find the closest size. Useful when markings have worn off, or for thrifted and circular needles without a readable label.
Confirm calibration
Calibrate your display for best accuracy before comparing objects.
Compare diameters
Compare the straight shaft of the needle, not the pointed tip.
Compare two diameters— side-by-side or overlay
Difference highlight uses calibrated --px-per-mm. Solid = A, dashed = B in overlay.
Can't find what you're measuring?
Knitting Needle Size Chart
Metric millimeters are the physical source of truth. US sizes follow the Craft Yarn Council chart. Legacy UK sizes are common conversion references only; makers can vary.
| Metric | Common US | Common UK / legacy |
|---|---|---|
| 2 mm | 0 | 14 |
| 2.25 mm | 1 | 13 |
| 2.75 mm | 2 | 12 |
| 3 mm | — | 11 |
| 3.25 mm | 3 | 10 |
| 3.5 mm | 4 | — |
| 3.75 mm | 5 | 9 |
| 4 mm | 6 | 8 |
| 4.5 mm | 7 | 7 |
| 5 mm | 8 | 6 |
| 5.5 mm | 9 | 5 |
| 6 mm | 10 | 4 |
| 6.5 mm | 10½ | 3 |
| 7 mm | — | 2 |
| 8 mm | 11 | 0 |
| 9 mm | 13 | 00 |
| 10 mm | 15 | 000 |
| 12.75 mm | 17 | — |
| 15 mm | 19 | — |
Source: Craft Yarn Council — Hooks & Needles. Closest standard size. Calibrate your display for best accuracy.
Common questions
How do I size an unmarked knitting needle?
Calibrate your screen and compare the straight shaft—not the tapered tip—to actual-size metric standards. US sizes follow the Craft Yarn Council chart as common references; millimeters remain the physical source of truth.
What is US size 8 in millimeters?
On this chart, US 8 is 5.0 mm. Prefer a stamped millimeter marking when available; letter and number systems can vary by maker.
Does this work for circular knitting needles?
Yes for shaft diameter. Compare a straight section of the needle tip where the diameter is consistent—not the cable, join, or tapered point.
Should I measure the pointed tip?
No. Measure the straight shaft. The tapered tip is not the sizing reference and will understate the diameter.
Are UK knitting needle sizes exact?
Legacy UK sizes here are common conversion references only. Makers can vary; rely on millimeters when they disagree.
How can I compare two needle sizes side by side?
Use Compare two diameters on this page to place two shaft sizes next to each other at calibrated actual size—helpful when choosing between nearby US or metric sizes.