US Size 1 Knitting Needles (2.25 mm): Yarn Weight, Gauge and Conversions
A US size 1 knitting needle is 2.25 mm in diameter, old UK and Canadian size 13. It suits lace and super fine (fingering) yarn, and super fine (fingering) knits at 27 to 32 stitches per 4 inches. At about 32 stitches per 4 inches, a 20 inch hat needs about 160 stitches and an 8 inch scarf about 64.
Knitting needle size is the diameter of the shaft, measured in millimeters. This needle is 2.25 mm, about 0.09 inch across. US size 1 is the American label for a 2.25 mm needle, and old UK and Canadian size 13 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 1 knitting needle in mm and old UK sizes?
| Metric | 2.25 mm |
|---|---|
| Inches (diameter) | 0.09 in |
| US size | 1 |
| Old UK and Canadian size | 13 |
| Crochet hook, same diameter | B-1 (2.25 mm) |
| Usual yarn weight | super fine (fingering) |
| Estimated gauge | about 32 stitches per 4 in |
What yarn weight goes with US 1 needles?
The Craft Yarn Council lists 2.25 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 |
|---|---|---|---|---|
| Lace | 1.5 to 2.25 mm (US 000 to 1) | 33 to 40 | 164 to 200 | 66 to 80 |
| 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 1 needles?
The estimated gauge places 2.25 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 32 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 160 |
| Snug hat, 18 in around | 18 in | about 144 |
| Cowl, 24 in around | 24 in | about 192 |
| Scarf, 8 in wide | 8 in | about 64 |
| Baby blanket, 42 in wide | 42 in | about 336 |
| Throw, 50 in wide | 50 in | about 400 |
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 1 (2.25 mm)
Clover Takumi Bamboo 7-Inch Double Point Knitting Needles, US 1 (2.25 mm), 5 Pack
$11.01Five 7 inch bamboo double points in US 1 (2.25 mm), a grippy, inexpensive way into socks.
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ChiaoGoo Stainless Steel Red Circular Knitting Needle, 9-Inch, US 1 (2.25 mm)
$13.99A 9 inch stainless steel circular in US 1 (2.25 mm), sized for sock tubes without double points.
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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.
Check pricePrices change often, so confirm on Amazon. As an Amazon Associate we earn from qualifying purchases.
What crochet hook matches a US 1 knitting needle?
The B-1 crochet hook is also 2.25 mm. Diameter is where the match ends, though: crochet fabric is denser, so CYC pairs super fine (fingering) yarn with 2.25 to 3.25 mm (US 1 to 3) needles but larger hooks. A 2.25 mm hook usually suits a lighter yarn than a 2.25 mm needle does.
What are the knitting needle sizes next to US 1?
Frequently asked questions
What size is a US 1 knitting needle in mm?
A US size 1 needle is 2.25 mm in diameter, about 0.09 inch. The old UK and Canadian size is 13. 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 0 (2 mm) and 2.5 mm.
What yarn weight do you use with US size 1 needles?
CYC places 2.25 mm inside the recommended needle range for lace and 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. Because 2.25 mm sits where two categories meet, it makes the lighter yarn slightly loose and the heavier yarn slightly firm. Your pattern gauge matters more than the category name.
How many stitches do I cast on for a hat with US 1 needles?
At about 32 stitches per 4 inches, our estimate for super fine (fingering) yarn on 2.25 mm needles, a 20 inch hat needs about 160 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 144 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 1 needles?
Cast on about 64 stitches for an 8 inch wide scarf at 32 stitches per 4 inches. A 6 inch scarf needs about 48 and a 10 inch scarf about 80. 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 1 knitting needle?
The B-1 crochet hook is also 2.25 mm, so the two share a diameter. 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 2.25 mm hook usually suits a lighter yarn than a 2.25 mm needle does.
Are US size 1 needles good for beginners?
They are better as a second or third project. At 2.25 mm the stitches are small, about 32 to every 4 inches, so a 20 inch hat is 160 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.