Knit & Crochet Lab

Count the stitches across the middle 4 inches (10 cm) of your blocked swatch, then divide by 4. For example, 20 stitches over 4 inches = 5 stitches per inch. Do the same for rows to get rows per inch. The gauge calculator above does this math and also works in centimeters. Always measure after blocking, because washing changes the fabric.

Use the rule of three: divide the pattern's stitch count by the pattern's gauge, then multiply by your gauge. Example: a pattern says cast on 100 stitches at a gauge of 5 stitches per inch, and your swatch gives 4.5 stitches per inch. 100 ÷ 5 = 20 inches of finished width; 20 × 4.5 = 90 stitches to cast on. The pattern-adjustment mode above runs this calculation for stitches and rows.

Multiply your stitch gauge by the finished width you want. At 5 stitches per inch, a 40-inch chest needs 5 × 40 = 200 stitches (in the round). Add wearing ease for a relaxed fit — 10% positive ease means 220 stitches — and round to a multiple of your stitch-pattern repeat. The garment-math mode above handles ease and repeat rounding automatically.

US 8 is 5.0 mm, which is UK size 6. The converter above translates any needle or hook size between US, metric (mm), and UK numbering, including both knitting needles and crochet hooks. Metric millimeters are the universal reference — when in doubt, match the mm, not the brand's label.

A 5 mm crochet hook is a US H-8 (UK size 6). Similarly, 5.5 mm is I-9, 6 mm is J-10, 4 mm is G-6, and 4.5 mm is just size 7 in US numbering. The hook converter above answers “what letter is a __mm hook” for every size, including the large Q and S hooks.

Match the millimeter diameter: a needle and a hook with the same shaft diameter are the same size. US 8 knitting needles (5.0 mm) equal a 5.0 mm crochet hook, which is US H-8. Enter any needle size in the converter above and it shows the equivalent crochet hook, or vice versa.

Japanese knitting needles are effectively sold by their millimeter diameter, so the metric column of the conversion table is the direct translation: a Japanese 5 mm needle is simply 5.0 mm, i.e. US 8 / UK 6. Older Japanese 号 (gō) numbers run roughly 2.1 mm at size 0 up to 6.6 mm at size 15. Use the mm value on the needle itself as the ground truth.

Published Craft Yarn Council-style estimates give ranges by yarn weight. A worsted-weight (#4) adult sweater takes roughly 1,125–1,625 yards; a worsted scarf 375–500 yards; a worsted baby blanket 1,000–1,125 yards; a worsted afghan 2,250–3,125 yards. Finer yarns need more yardage for the same project. The yardage mode above looks up the full table by project, yarn weight, and sweater size.

It depends on the yarn weight: 300 g of worsted (#4, about 220 yards per 100 g) is roughly 660 yards; 300 g of fingering (#1, about 430 yards per 100 g) is roughly 1,290 yards; 300 g of bulky (#5, about 130 yards per 100 g) is roughly 390 yards. The weight converter above uses typical yards-per-100g values per weight class — check your specific ball band for the exact number.

Divide the estimated total yardage by the yardage printed on one skein, then round up. Example: you need about 1,375 yards for a sweater and each skein holds 220 yards — 1,375 ÷ 220 = 6.25, so buy 7 skeins. Adding a 10% safety buffer covers swatching and mistakes. The yardage calculator above does this division and the buffer math for you.

Yarn weight numbers are the Craft Yarn Council standard: #4 Medium (worsted/aran, knit on US 7–9 / 4.5–5.5 mm) is the all-purpose default, while #5 Bulky (chunky, US 9–11 / 5.5–8 mm) is thicker and works up faster. Lower numbers mean thinner yarn. The standard runs 0 (Lace) to 7 (Jumbo); the yarn-weight table on this page lists every class with its needle and hook ranges.

Medium worsted-weight yarn (#4) with US 8 (5.0 mm) knitting needles or an H-8 (5.0 mm) crochet hook. The stitches are big enough to see and fix, small enough to look neat, and the yarn is cheap and widely available. The beginner recommender above suggests the exact yarn, needle, and hook for ten common first projects.

A scarf (flat, no shaping), a cotton dishcloth (small and fast), or crochet granny squares (one motif repeated). All three use worsted yarn and a 5 mm needle or hook, so the beginner recommender above covers them. Save fitted garments like sweaters for after you are comfortable reading your stitches — and swatch first.

For anything that doesn't need to fit a body — scarves, blankets, dishcloths — an exact swatch is optional, but a quick one still teaches you your natural tension and shows how the yarn behaves after washing. For sweaters, hats, and socks, always swatch: a half-stitch-per-inch error over 200 stitches is a 20-inch mistake. Block the swatch exactly as you will wash the finished piece.

Yes, but match the gauge, not the label: knit a swatch in the substitute yarn and check stitches per inch against the pattern's gauge. If they match, use the pattern-adjustment mode to convert stitch counts anyway — row gauge often differs even when stitch gauge matches. Then re-estimate yardage, because a different weight changes how many yards the project eats.

Yes. Every calculation on this page runs entirely in your browser — your swatch numbers, measurements, and project plans never leave your device, and there are no accounts, no tracking scripts, and no network requests. Once the page is loaded it works offline too.