How to Substitute Yarn

A common misconception is that all yarns are alike, and that substituting one for another is merely a process of swapping needle sizes until it knits at your pattern’s intended gauge. At the other end of the spectrum are knitters who live in fear of varying at all from a pattern’s requirements, even if it means working with a yarn they don’t particularly like.

Whether your substitution is inspired by allergies, finances, availability, or aesthetics, it takes just a few extra minutes to think through the substitution process. I promise you, the end results will be worth it.

Yarns generally fall into seven categories of weight and gauge. Many patterns and online yarn shops list yarns using these naming conventions, so it’s important to know the general category of yarn your pattern calls for.

The following are based on the Craft Yarn Council’s Yarn Standards chart. Keep in mind that these categories and their numbers can differ from older conventions, and they still leave a bit of wiggle room in gauge.

Terms Defined

CYCA number	Weight	Gauge
0	Lace (Fingering)	33-40 sts = 4″ (10cm)
1	Superfine (Sock/Fingering/Baby)	27-32 sts = 4″ (10cm)
2	Fine (Sport/Baby)	23-26 sts = 4″ (10cm)
3	Light (DK/Light Worsted)	21-24 sts = 4″ (10cm)
4	Medium (Worsted/Afghan/Aran)	16-20 sts = 4″ (10cm)
5	Bulky (Chunky/Craft/Rug)	12-15 sts = 4″ (10cm)
6	Super Bulky (Roving)	6-11 sts = 4″ (10cm)
7	Jumbo	6 sts and fewer = 4″ (10cm)

Gauge or Needle Size?

The gauge is your most important number for a pattern. Needle sizes are given as guidelines only. The idea is that you’ll use whatever needle size it takes to achieve the desired gauge.

Gauge Gotchas

Although most patterns specify gauge in terms of stockinette stitch, a few note the gauge in terms of a specific stitch pattern.

If this is the case with your pattern, you’ll need to look up the manufacturer’s given gauge for the yarn in question. You can do this either online (Ravelry has a vast store of user-generated yarn information, and the yarn data on Yarndex sometimes includes scans of current and older color cards).

If you’re using an older pattern that calls for long-gone yarns, try checking Laurie Kynaston’s extensive online listing of older, discontinued yarns sorted by weight and, in several cases, by manufacturer. She includes fiber content, skein weight, and yardage.

Failing this, you can always swatch the yarn and let it show you its ideal gauge. When the label isn’t handy, simply double the yarn and run it through the holes in your needle sizer until you find a hole in which the yarn slides not too tightly and not too loosely. That’s your starting needle size.

Sizing Conventions

Patterns also differ in the size of their gauge swatches. You’ll normally find gauge given in terms of stitches per 4 inches or 10cm, but sometimes you’ll see it in terms of stitches per inch or per 2 inches. Not all labels follow the same standard, so double-check this number if anything seems off.

Let It Be

Most important, try to respect a yarn’s given gauge. Forcing a yarn into a tighter or looser gauge simply because you like the yarn isn’t always a wise choice.

Imagine a tea bag designed to make the perfect 8-ounce cup of tea. Use it in only 4 ounces of water, or drown it in 16 ounces, and it won’t taste the same. In the case of knitting, you can easily end up with fabric that’s awkwardly loose or, conversely, so tight that it stands up by itself.

A general rule of thumb is to stay within a half-stitch-per-inch range of the yarn originally specified in the pattern.

Time to Shop!

Once you’ve determined the yarn weight and gauge your pattern needs, you can begin investigating your yarn options. If you don’t have a yarn store near you, go online. Most online yarn stores let you browse yarns by gauge, fiber, and manufacturer.

Part 2: Determining How Much Yarn You’ll Need

Unfortunately, you can’t simply go by the number of skeins your pattern requires. Different yarn manufacturers pack different amounts of yarn into their skeins.

Find the Magic Number

Your first task is to figure out how many yards/meters your pattern requires. Many new patterns include this information.

If your pattern doesn’t show the total yardage required, check to see if it lists how many yards/meters are in each skein of the yarn specified in the pattern. If this is the case, simply multiply the number of skeins required by the number of yards in each skein. Voila, there’s your magic number.

Keep your calculator handy because once you’ve picked your substitute, you’ll need to convert your yardage

back into skeins again. To do this, simply divide your pattern’s total required yardage by the number of yards in each substitute skein. This tells you how many skeins you’ll need. When in doubt, round up.

Working with Weight

For a while there, pattern designers had the frustrating habit of basing their patterns on yarn category and weight alone, with no mention of yardage. For example, they’d call for 16 ounces of worsted-weight yarn, period.

In most cases those patterns also specifed the desired gauge, which is a much more accurate clue. With this number in mind, visit any of the popular online shops, or go to your local store, and look at yarns that knit up at a similar gauge.

Once you’ve picked a yarn you like, simply divide the total required weight (in my example, 16 oz) by the weight of each skein. This tells you the total number of skeins you’ll need for your pattern.

A word of caution: Yarn weights tend to vary more than yards, so you may want to add another skein to your stash to play it safe. Read more about using a scale to determine the yardage of skeins.

Part 3: Working with Handspun Yarns

Handspinners have the distinct advantage of being able to create custom yarns exactly to their specifications. Unfortunately, their yarns don’t come with labels specifying their gauge and yardage.

To determine the gauge of your handspun yarn, you must use the “wraps per inch” unit of measurement, also known as WPI. Here’s how to do it.

Using a standard ruler, start wrapping your handspun yarn around the ruler, being careful not to overlap the strands or create gaps between them. Once you’ve wrapped your yarn around an inch of the ruler, simply count the number of wraps you made.

Then, use the chart below to find the closest corresponding gauge, yarn category, and needle size that will work for your yarn. You can use this information to match your handspun with the best pattern.

WPI	Category	Gauge	Needle (U.S.)
19-22	Fingering	7-8 sts = 1″	1-3
14-19	Sport	6-6.5 sts = 1″	4-6
11-13	DK	5.5-6 sts = 1″	5-7
10-12	Worsted	4-5.5 sts = 1″	7-9
8-10	Bulky	3-3.5 sts = 1″	10-11
4-8	Superbulky / Polar	1.5-3.5 sts = 1″	13-17

Part 4: Textural and Aesthetic Considerations

Beyond gauge, yardage, and accurate swatches, you must always keep in mind: Does your substitute yarn match the overall look and feel of the original one?

For example, if your original pattern uses a smooth yarn to highlight the pattern’s elaborate stitchwork, you want to stick with a similarly smooth substitute.

Likewise, if the original yarn has any special texture, you’ll want to respect this. Examples of textured yarns include bouclé, slubby, thick-and-thin, furry, eyelash, or other novelty yarns. Depending on the pattern, even brushed mohair could fall into this category.

If your pattern calls for such yarns, pay extra attention to finding a similar-textured replacement. It will make a difference.

Different Spins

Even seemingly simple yarns can produce different surface textures, drapes, and stitch definitions depending on how they are spun. The subjects of twist, ply, and fibers make up the heart of my book, The Knitter’s Book of Yarn.

Bottom line: The more plies you add to a yarn, the more rounded it becomes and the greater definition it gives to your stitches. Yarns made up of many plied strands plied together, such as Filatura di Crosa Zara, tend to produce the most spongy fabrics with bright, clear stitches. Yarns with four and even three plies still render your stitches with fullness and clarity.

But when you get down to just two plies, things change. The ply shadows deepen, and your stitches take on a slightly wobbly, cobblestoned look. Pure stockinette in a two-ply yarn—especially one whose plies are tightly twisted almost perpendicular to the direction of the fibers—will not be the same as it is in a smooth three- or four-ply yarn.

Fiber Composition

Matching fiber types is only important if you’re working with yarns whose fibers play an integral part in their overall aesthetic. Angora, brushed mohair, and baby alpaca are prime examples of fibers that produce a fuzzy effect, while silk, bamboo, and Tencel are all about drape and sheen. Even among the same fibers, if they are spun woolen (as is the wool in Brooklyn Tweed Shelter), they will create a blurrier fabric than would a smooth worsted-spun wool (such as Elsa Wool Company’s worsted-spun Cormo).

Even in this realm, however, you have leeway in choosing the precise fiber combination. For example, if your pattern calls for a pricey pure Angora yarn, you can substitute a less-expensive angora/wool blend and still achieve a similar visual effect.Part 5: Fine-Tuning Your Swatches

If your swatch produces more stitches per inch than specified in the pattern, you’ll need to switch to a larger needle. Likewise, if your swatch has fewer stitches per inch than required, you’ll need to try a smaller needle.

Here’s something else to keep in mind. Some knitters have a different gauge on knit rows than on purl rows—with the purl rows often being looser. Look at your stitches closely to see if each row is, indeed, the same height. If not, consider using a needle that’s one size smaller for your purl rows. Most patterns are worked back and forth, so it’s simply a matter of using two mis-matched needles interchangeably throughout.

If you’re working in the round, you won’t have to worry about this. Stockinette in the round involves knitting all rows; reverse-stockinette involves purling all rows. Any purl stitches will create purl ridges that conceal any gauge irregularity.

In terms of changing needle sizes to get gauge, most knitters find they need only to go up or down by one needle size to achieve the desired results.

Needle Gluttony?

Many beginning knitters cringe at the idea of purchasing multiple sets of needles just so they can reach the right gauge in a pattern. This is understandable because needles are a considerate investment.

But here’s the truth. While cooks need just a few knives to do all their work, knitters need needles. Lots and lots of needles. We need to have options and choices so that we can find the right size, tip style, and even material that will work best with the right yarn—which will, in turn, help us match the right yarn to the right project.

You’ll be grateful you did. Even duplicate sets of needles in the same size come in handy, especially if you like to have more than one project going at a time.

While your well-loved needles are waiting their turn, why not put them in a vase? They’re prettier than flowers, you never need to water them, and they’ll last forever.