3 mm Knitting Needles (US 3 or 2.5): Yarn Weight, Gauge and Conversions
A US size 3 knitting needle is 3 mm in diameter, old UK and Canadian size 11. It suits super fine (fingering) yarn, which knits at 27 to 32 stitches per 4 inches. At about 28.5 stitches per 4 inches, a 20 inch hat needs about 144 stitches and an 8 inch scarf about 57.
Knitting needle size is the diameter of the shaft, measured in millimeters. This needle is 3 mm, about 0.12 inch across. US size 3 is the American label for a 3 mm needle, and old UK and Canadian size 11 is the same needle. The millimeter figure is the one that matches across every brand, so it is printed on most needles and needle gauges.
What is a US 3 knitting needle in mm and old UK sizes?
| Metric | 3 mm |
|---|---|
| Inches (diameter) | 0.12 in |
| US size | 3 |
| Old UK and Canadian size | 11 |
| Crochet hook, same diameter | None on the CYC chart |
| Usual yarn weight | super fine (fingering) |
| Estimated gauge | about 28.5 stitches per 4 in |
Chart note
CYC lists 3 mm as US 3; other charts list US 2.5 or no US size.
What yarn weight goes with US 3 needles?
The Craft Yarn Council lists 3 mm inside the recommended needle range for the yarn weights below. The hat and scarf columns show how many stitches the full gauge range of each weight gives, so you can see how much the yarn choice moves the numbers.
| Yarn weight | CYC needle range | Gauge per 4 in | 20 in hat | 8 in scarf |
|---|---|---|---|---|
| Super fine (fingering) | 2.25 to 3.25 mm (US 1 to 3) | 27 to 32 | 136 to 160 | 54 to 64 |
How many stitches do you cast on with US 3 needles?
The estimated gauge places 3 mm within the CYC range for super fine (fingering) yarn: the smallest recommended needle gets the most stitches per 4 inches and the largest gets the fewest. That gives about 28.5 stitches per 4 inches on this needle. Circular pieces are rounded to a multiple of 4 so 2x2 ribbing works out.
| Piece | Width or circumference | Cast on (estimate) |
|---|---|---|
| Hat, 20 in around (multiple of 4) | 20 in | about 144 |
| Snug hat, 18 in around | 18 in | about 128 |
| Cowl, 24 in around | 24 in | about 172 |
| Scarf, 8 in wide | 8 in | about 57 |
| Baby blanket, 42 in wide | 42 in | about 299 |
| Throw, 50 in wide | 50 in | about 356 |
Swatch before you trust any cast-on number
Knit a swatch at least 6 inches wide, wash and dry it the way you will treat the finished piece, then count stitches across the center 4 inches. Put your real number into the cast-on calculator for an exact count.
Needles and supplies for US 3 (3 mm)
ChiaoGoo Twist Red Lace Double Point Needle Set, 6 inch, US 0 to 3
$74.89Six inch stainless steel double points in US 0, 1, 1.5, 2, 2.5 and 3, the fine sizes socks and lace use.
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ChiaoGoo Twist Shorties Red Lace Interchangeable Set, 2 and 3 inch tips, US 0 to 3
$117.20Short 2 and 3 inch interchangeable tips in US 0 to 3 with 5, 6 and 8 inch cables for small circumferences.
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HiyaHiya Flyers Flexible Double-Pointed Needles, Sock Set
$119.91Sharp 8 inch double points from 2.25 to 3 mm, a dedicated set for sock knitters.
Check pricePrices change often, so confirm on Amazon. As an Amazon Associate we earn from qualifying purchases.
What crochet hook matches a US 3 knitting needle?
No standard crochet hook is exactly 3 mm on the CYC chart. The nearest are C-2 (2.75 mm) and D (3.125 mm). For the same yarn, crochet usually calls for a bigger tool than knitting.
What are the knitting needle sizes next to US 3?
Frequently asked questions
What size is a US 3 knitting needle in mm?
A US size 3 needle is 3 mm in diameter, about 0.12 inch. The old UK and Canadian size is 11. CYC lists 3 mm as US 3; other charts list US 2.5 or no US size. US numbers were never fully standardized, so trust the millimeter size printed on the needle or check it in a needle gauge. The neighboring sizes are US 2 (2.75 mm) and US 3 (3.25 mm).
What yarn weight do you use with US size 3 needles?
CYC places 3 mm inside the recommended needle range for super fine (fingering) yarn. Super fine (fingering) is the usual match: its range is 2.25 to 3.25 mm (US 1 to 3), knitting at 27 to 32 stitches per 4 inches. The size sits inside a single category, so it is a straightforward match. Your pattern gauge matters more than the category name.
How many stitches do I cast on for a hat with US 3 needles?
At about 28.5 stitches per 4 inches, our estimate for super fine (fingering) yarn on 3 mm needles, a 20 inch hat needs about 144 stitches, rounded to a multiple of 4 for ribbing. For a snug fit many patterns size the hat 1 to 2 inches smaller than the head, which is about 128 stitches at 18 inches. The estimate places the needle within the CYC gauge range, so knit a swatch and recount before you cast on.
How many stitches for a scarf on US 3 needles?
Cast on about 57 stitches for an 8 inch wide scarf at 28.5 stitches per 4 inches. A 6 inch scarf needs about 43 and a 10 inch scarf about 71. Stitch pattern changes both width and yarn: garter stitch used about 46 percent more yarn than stockinette in one test. A quick 4 inch swatch in the stitch you plan to use gives a better count than the label gauge.
What crochet hook is the same size as a US 3 knitting needle?
No standard crochet hook is exactly 3 mm on the CYC chart. The nearest are C-2 (2.75 mm) and D (3.125 mm). They are not interchangeable for the same yarn, though. CYC pairs super fine (fingering) yarn with 2.25 to 3.25 mm (US 1 to 3) needles but 2.25 to 3.5 mm (B-1 to E-4) hooks, because crochet fabric is denser. A 3 mm hook usually suits a lighter yarn than a 3 mm needle does.
Are US size 3 needles good for beginners?
They are better as a second or third project. At 3 mm the stitches are small, about 28.5 to every 4 inches, so a 20 inch hat is 144 stitches around and progress feels slow. Good light helps a great deal, and if fine needles make your hands ache, ergonomic or square needles and short sessions help.
How we research: we compare manufacturer specifications, owner manuals, published standards and recurring themes in verified owner reviews. We do not test products in person, and this is researched guidance, not professional advice. Follow your machine manual and pattern, and take care with rotary cutters, hot irons and needles. As an Amazon Associate we earn from qualifying purchases.