You need to know how much yarn to buy whenever you start a new knitting or crocheting project. You can figure out the yardage by using yarn calculations, whether you’re substituting one yarn for another in a pattern or whether you just have a general sense of what you’d like to knit.
If you’re using the yarn called for in a pattern, the pattern usually tells you how many balls to buy for each size.
However, if you choose to use a yarn different from the pattern’s suggestion, you may need to do a little calculating:
Number of skeins called for in the pattern × yards per skein = total yards needed for the pattern
Total yards needed for the pattern ÷ yards per skein of your chosen yarn = number of skeins you need (round up to the nearest whole number, if necessary)
If you aren’t working directly from a pattern or are working at a different gauge than a pattern recommends, you don’t have a tidy way to determine how much yarn to buy. Estimate how much you need. This table gives yardage approximations for various projects in a variety of gauges.
| Yarn Weight Category | Stitches per Inch | Yards Needed for a Hat | Yards Needed for a Scarf | Yards Needed for an Adult Sweater |
|---|---|---|---|---|
| 1 Superfine | 7 to 8 | 300 to 375 | 350 | 1,500 to 3,200 |
| 2 Fine | 6 to 7 | 250 to 350 | 300 | 1,200 to 2,500 |
| 3 Light | 5 to 6 | 200 to 300 | 250 | 1,000 to 2,000 |
| 4 Medium | 4 to 5 | 150 to 250 | 200 | 800 to 1,500 |
| 5 Bulky | 3 to 4 | 125 to 200 | 150 | 600 to 1,200 |
| 6 Super bulky | 1.5 to 3 | 75 to 125 | 125 | 400 to 800 |
Patterns usually call for a little more yarn than you’ll actually use, but because you want to swatch and account for the unknown (you actually hate three-quarter sleeves, or you've had some terrible yarn accident), buy a little extra yarn, particularly if it’s being discontinued. A ribbed or cabled pattern takes more yarn than stockinette stitch, and your knitting may vary.