Knitting & Crochet Gauge Swatch Converter
Recalculate cast-on stitches and rows when your swatch gauge differs from your knitting or crochet pattern, with needle size guidance.
1. Pattern Gauge (What the Pattern Calls For)
2. Your Swatch Gauge (What You Actually Knit)
Standard Knitting Needle & Crochet Hook Conversion Guide
| Metric (mm) | US Knitting | US Crochet | UK / Canadian | Standard Yarn Weight |
|---|---|---|---|---|
| 2.25 mm | US 1 | B-1 | 13 | Fingering / Sock (1) |
| 2.75 mm | US 2 | C-2 | 12 | Fingering / Sock (1) |
| 3.25 mm | US 3 | D-3 | 10 | Sport Weight (2) |
| 3.75 mm | US 5 | F-5 | 9 | DK / Light Worsted (3) |
| 4.00 mm | US 6 | G-6 | 8 | DK / Worsted (3-4) |
| 4.50 mm | US 7 | 7 | 7 | Worsted / Afghan (4) |
| 5.00 mm | US 8 | H-8 | 6 | Worsted / Heavy Worsted (4) |
| 5.50 mm | US 9 | I-9 | 5 | Chunky / Bulky (5) |
| 6.00 mm | US 10 | J-10 | 4 | Bulky (5) |
| 8.00 mm | US 11 | L-11 | 0 | Super Bulky (6) |
About this tool
How to use it
- Enter the pattern gauge specifications (number of stitches and rows per 4 inches / 10 cm) and the pattern cast-on number.
- Measure your washed and blocked test swatch, then input your actual stitches and rows per 4 inches.
- Click Recalculate Gauge & Stitches to discover your new adjusted cast-on count and see how your finished dimensions change.
- Review needle size recommendations to decide whether changing needle sizes or recalculating stitches is simpler.
Why it matters
Every knitter and crocheter holds yarn with unique tension. Even when using the exact needle size and yarn recommended in a pattern, an innocent variance of just 1 stitch per 4 inches can result in a sweater that is 3 inches too large or small across a 40-inch chest.
When to use it
Use this tool after knitting your gauge swatch before beginning any sweater, cardigan, sock, or fitted garment project, or when substituting a different yarn weight than the designer specified.
Good to know
Always wash and block your swatch before measuring! Yarns (especially wool and alpaca) grow and bloom significantly after soaking in water and laying flat to dry.
Common questions
Why is a 4-inch (10 cm) swatch standard?
Measuring edge stitches is inaccurate because border tension differs from the center of work. A 4-inch square provides enough internal stitches to calculate a reliable stitches-per-inch average.
Should I change needle sizes or recalculate the pattern?
For garments with complex lace, cables, or textured stitch repeats, changing needle sizes to meet the pattern gauge is usually easier. For simple stockinette or raglan designs, recalculating cast-on numbers is often fastest.
What does going up or down a needle size do to gauge?
Using a larger needle produces larger loops, resulting in fewer stitches per inch (loosening gauge). Using a smaller needle produces tighter stitches, resulting in more stitches per inch.
Does row gauge matter as much as stitch gauge?
Stitch gauge (width) is critical because it dictates fit around the body. Row gauge (height) is often easier to adjust on the fly because most patterns say 'knit until work measures 15 inches from cast-on'.