US Size 8 Knitting Needles (5 mm): Yarn Weight, Gauge and Conversions
A US size 8 knitting needle is 5 mm in diameter, old UK and Canadian size 6. It suits medium (worsted) yarn, which knits at 16 to 20 stitches per 4 inches. At about 18 stitches per 4 inches, a 20 inch hat needs about 92 stitches and an 8 inch scarf about 36.
Knitting needle size is the diameter of the shaft, measured in millimeters. This needle is 5 mm, about 0.20 inch across. US size 8 is the American label for a 5 mm needle, and old UK and Canadian size 6 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 8 knitting needle in mm and old UK sizes?
| Metric | 5 mm |
|---|---|
| Inches (diameter) | 0.20 in |
| US size | 8 |
| Old UK and Canadian size | 6 |
| Crochet hook, same diameter | H-8 (5 mm) |
| Usual yarn weight | medium (worsted) |
| Estimated gauge | about 18 stitches per 4 in |
What yarn weight goes with US 8 needles?
The Craft Yarn Council lists 5 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 |
|---|---|---|---|---|
| Medium (worsted) | 4.5 to 5.5 mm (US 7 to 9) | 16 to 20 | 80 to 100 | 32 to 40 |
How many stitches do you cast on with US 8 needles?
The estimated gauge places 5 mm within the CYC range for medium (worsted) yarn: the smallest recommended needle gets the most stitches per 4 inches and the largest gets the fewest. That gives about 18 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 92 |
| Snug hat, 18 in around | 18 in | about 80 |
| Cowl, 24 in around | 24 in | about 108 |
| Scarf, 8 in wide | 8 in | about 36 |
| Baby blanket, 42 in wide | 42 in | about 189 |
| Throw, 50 in wide | 50 in | about 225 |
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 8 (5 mm)
Clover Takumi Bamboo 9-Inch Single Point Knitting Needles, US 8
$11.95A 9 inch bamboo straight pair in US 8 (5 mm), a light, inexpensive single-point needle.
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Kollage Square Circular Knitting Needle, 32-Inch, Firm Cable, US 8 (5 mm)
$18.89A square-shaft US 8 (5 mm) circular with a lifetime warranty, a shape many knitters with achy hands prefer.
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Prym Ergonomics 14-Inch Single Point Knitting Needles, US 8 (2 Pack)
$8.39Lightweight 14 inch US 8 straights with a round tip and a triangular body designed for grip.
Check pricePrices change often, so confirm on Amazon. As an Amazon Associate we earn from qualifying purchases.
What crochet hook matches a US 8 knitting needle?
The H-8 crochet hook is also 5 mm. Diameter is where the match ends, though: crochet fabric is denser, so CYC pairs medium (worsted) yarn with 4.5 to 5.5 mm (US 7 to 9) needles but larger hooks. A 5 mm hook usually suits a lighter yarn than a 5 mm needle does.
What are the knitting needle sizes next to US 8?
Frequently asked questions
What size is a US 8 knitting needle in mm?
A US size 8 needle is 5 mm in diameter, about 0.20 inch. The old UK and Canadian size is 6. 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 7 (4.5 mm) and US 9 (5.5 mm).
What yarn weight do you use with US size 8 needles?
CYC places 5 mm inside the recommended needle range for medium (worsted) yarn. Medium (worsted) is the usual match: its range is 4.5 to 5.5 mm (US 7 to 9), knitting at 16 to 20 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 8 needles?
At about 18 stitches per 4 inches, our estimate for medium (worsted) yarn on 5 mm needles, a 20 inch hat needs about 92 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 80 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 8 needles?
Cast on about 36 stitches for an 8 inch wide scarf at 18 stitches per 4 inches. A 6 inch scarf needs about 27 and a 10 inch scarf about 45. 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 8 knitting needle?
The H-8 crochet hook is also 5 mm, so the two share a diameter. They are not interchangeable for the same yarn, though. CYC pairs medium (worsted) yarn with 4.5 to 5.5 mm (US 7 to 9) needles but 5.5 to 6.5 mm (I-9 to K-10.5) hooks, because crochet fabric is denser. A 5 mm hook usually suits a lighter yarn than a 5 mm needle does.
Are US size 8 needles good for beginners?
Yes. 5 mm needles with medium (worsted) yarn make stitches large enough to see and count, and a 20 inch hat is only about 92 stitches around, so projects grow quickly. Smooth, light-colored yarn makes mistakes easier to spot. If your hands ache, square or triangular ergonomic needles in this size are worth trying.
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.