From the title, you may think this is a metaphysical dissertation on whether it's possible to have enough yarn. Philosophers continue to debate the question, but I believe we all know the answer... deep down. So, moving on, this is a post about how to estimate whether you have enough yarn in your stash for a particular project.
Step 1. Calculate the number of square inches for your size.
This is a quick way to roughly calculate the number of square inches/centimeters. Generally your pattern will have a schematic. Find your size. Multiply the finished chest by the total length. Then multiply the finished length of the sleeve (from underarm to cuff) by the width of the sleeve at the underarm. Add these two numbers together, and there you have it. A size large, for example, is (49" x 23") plus (14" x 18" x 2) = 1631 square inches.
Step 2. Make your swatch
Let's use my Angelica Cardigan as an example, because lace is so variable. For a size large, the pattern calls for 7 skeins of sport-weight yarn, or about 1350 yards, knit with size US 4 needles. Suppose you've been wanting to combine a fingering-weight (like Hedgehog Fibres "Skinny Singles") with Rowan's KidSilk Haze, a lace-weight mohair. For this combination, a size US 8 needle would work well. Make a large swatch of the main stitch pattern, in this case the Angelica Lace pattern. Use 20 yards of yarn for your swatch, and knit the swatch without adding any borders -- this is important. Jot down the unblocked width and length of your swatch, because you can always use these numbers to double-check your gauge at anytime during the project. Then block your swatch and lay flat to dry just as you will your sweater. Wait one day (this is slow fashion, after all).
Step 3. The yardage estimate
Multiply the total width by the total length of your swatch (mine is 6" wide x 5" in length = 30 square inches). So now I just divide the total number of square inches by the square inches in my swatch, then multiply the result by the 20 yards I used in the swatch. My estimated yardage is 1631 divided by 30 times 20 = 1087 yards. I'll need approximately 1087 yards of each yarn. This number is an over-estimate, allowing extra for swatching.
For a more accurate estimate, use a personalized pattern available on KnitWiz (or design your own). The Angelica Cardigan will be published on April 2nd, 2024. In this case, skip step one. Enter your total yardages in the yarn section of your project page and then scroll back up to the top. Your yardage estimate is automatically recalculated for you.
May the sun shine on your knitting, may your skeins never tangle, and have a great day!