How to choose yarn for a knitting project

1. Start from the pattern's gauge

If you have a pattern, it has already made the first decision: the weight. Its gauge — stitches over 4" — is the number the yarn has to hit, and the weight name on the ball band is only how you find candidates. Worsted for most sweaters, hats and blankets; DK for lighter garments and baby things; fingering for socks and shawls; chunky and bulky for speed. The yarn weights guide has the scale, and the substitution guide is for the case where the pattern names a yarn you do not want.

If you have no pattern yet, decide the weight by the project and the time you have: a worsted sweater is a month of evenings, a fingering one is three.

2. Decide how it will be washed

This is the step people skip, and it decides the fiber more than anything else. A garment for a child, a gift for someone who does not knit, socks, or anything that will go in a machine wants superwash wool, cotton, or a blend built to be washed. A sweater you will hand-wash twice a winter can be anything. Non-superwash wool is softer, warmer and cheaper per yard, and it felts the first time someone forgets. The superwash guide is the long version; the superwash merino and baby shelves are the machine-washable sets.

3. Who wears it, and where on the body

Against the neck and wrists — a cowl, a scarf, a crew-neck sweater — the yarn has to be soft: merino, baby alpaca, cashmere blends, silk. Over a shirt, a coarser and tougher wool is fine and lasts longer. For warmth, alpaca and wool; for cool, cotton and linen. For something that holds its shape — ribbing, a fitted cardigan — wool or a wool blend, because cotton and alpaca grow. For drape — a shawl, a loose summer top — the opposite. The fiber comparison puts all of that in one table.

4. Match the yarn to the stitch pattern

Cables, lace and textured stitches want a smooth, plied, solid-colored yarn so the stitches show. Plain stockinette and garter are where a single-ply, a halo, a tweed or a hand-dyed colorway can carry the design instead. Self-striping and gradient yarns want simple fabric and a width they were dyed for. A variegated hand-dye fights a cable; a solid worsted makes it sing. The single-ply vs plied and self-striping guides cover the two biggest traps.

5. Yardage and budget

Count by yards, not skeins: a sweater is a total yardage, and a 100 g skein holds anywhere from 90 to 450 yards depending on the weight. The pattern's total divided by the skein's yards, rounded up plus one, is the number of skeins; multiplied by the price, it is the cost of the project, and that is the number to compare yarns on. The sweater, blanket and hat and scarf guides have the totals, and every yarn page here has a calculator.

6. Then the color

Last, because the steps above have narrowed the field to a few lines, and now the color card is the fun part. A solid or heather shows texture; a kettle-dyed semi-solid gives depth to plain fabric; a variegated or striping yarn is the design. The Color Board puts colorways from different lines side by side, which is how to pick a body and a trim. Buy the whole project at once so the skeins share a dye lot — the dye lot guide says why.

The short version, by project