2 Ways to Estimate Yarn Requirements for a Sweater May 7, 2016 06:13 3 Comments

Designers and crafters alike can benefit from knowing how to estimate how much yarn is needed to knit (or crochet) a sweater.

For anyone who buys yarn—knowing how much to buy for a project can help prevent yarn chicken down the road, which makes things less stressful and more enjoyable.

For designers—more and more publishers seem to be requiring design submissions to include an estimate of approximately how much yarn will be needed for the sample project.

I have 2 ways of doing this, depending on the time I have available to the task.

The Quick and Easy Way:

I confess that I use this way more often than not. I've designed and knit enough sweaters in my life to feel comfortable trusting my gut instinct about how much yarn a project will use. But, I'm not always right. This technique is quick and easy, but not the most accurate. Sometimes I'll need to order another ball or 2 mid project… Here's what I do:

I log on to Ravelry and look up the yarn I've chosen for my design. Then I take a look at all the completed sweater projects knitters have made using that yarn. I look for projects that are about the same size and shape of the sweater I've designed. If the knitter has included how much yarn it took to make their sweater, I take note of it, and look for more. I usually look for at least 4 or 5, then trust my gut and go with what seems the most accurate, erring on the side of more than needed.

It's quick and easy. But, if I have more time, or if it's more critical that I'm accurate, I do this instead:

The More Accurate Way

Knit a swatch using the same needle size, yarn and stitch pattern that you intend to use in the sweater. Wash it, and lay it flat to dry.

While you're waiting for it to dry, you get to do a little math. Probably best done after a cup of coffee, or a good exercise session, or when you're nice and alert.

If you have a schematic drawn up, that will be useful. If not, then fill in these measurements:

Body Length (from hem to underarms): ______

Body Circumference (or the widths of back and front(s) added together): ________

Measurement across the shoulders (for set-in sleeves only): _____

Neck Circumference (for yokes and raglans): _______

Lower Yoke Circumference (around top of sleeves and body on first row of yoke; for yokes and raglans): ______

Armhole Depth: ________; or Yoke/Raglan Depth: ______

Sleeve Length: ______; Cap Depth: _____

Sleeve Cuff Circumference: ______; Sleeve Underarm Circumference: _______

Neckband Width: ______; Neckband Length: _____

Buttonband Width: _______: Buttonband Length: _____

Once you have the measurements filled in for your sweater, figure out the square inches by following the formulas below for the type of sweater you're making.

Set-In Sleeves:

Body: body circumference x body length = ______
Upper Back and Front: across-shoulder width x armhole depth x 2 = ______
2 Sleeves: (cuff circumference + underarm circumference) x length = ______
2 Sleeve Caps: underarm circumference x cap depth = ______
Neckbands and Buttonbands: width x length for each band = ______

Yoke or Raglan:

Body: body circumference x body length = ______
Yoke: [(lower yoke circumference + neck circumference) x raglan or yoke depth] ÷ 2 = ______
2 Sleeves:  (cuff circumference + underarm circumference) x length = ______
Neckbands and Buttonbands: width x length = ______

Add them all together for the total square inches of your sweater.

Once your swatch is dry, use a kitchen scale to determine the weight in grams. Then measure the width and length of your swatch. Multiply the width and length to get the total square inches of your swatch.

Now comes the fun part, where all this work comes together into a result. Ready?

Divide the weight of your swatch by the number of square inches in your swatch for a magic number.

Multiply the magic number by the total number of square inches in your sweater. This tells you how much your sweater will weigh, in grams.

I usually add about 10–15% for some wiggle room, then divide that number by the number of grams per skein. Now you know how many skeins of yarn to request for your sweater!

If you need to know yardage, simply multiply the number of skeins by how many yards are in each skein.

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