There are many numbers and categories that describe yarn and fiber—30/2, eight-ply weight, DK weight, yards per pound—but what do these numbers really tell you about your own yarn and projects?
Sometimes, the numbers have quantitative meaning (grist, count, etc.). Other times, the numbers represent an order or category, not a size (for example, Craft Yarn Council yarn weights). Before we go further, remember the numbers and names associated with fiber and yarn are just guidelines. Use your own hands to decide whether a fiber is fine or coarse, softly or densely spun. Weave a sample to decide whether a yarn is right for your project. Take comfort in knowing that handmade fiber arts projects do not need the same precision as getting an astronaut to the moon and back or for specifying a yarn for a run of 25,000 worsted-wool sweater vests.
Many of the numbers are intended to characterize the thickness or diameter of yarn. However, within each measurement system, you need to be aware of what the numbers mean relative to the yarn thickness. See Figure 1.
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Numbers and categories that describe the thickness of millspun (commercially produced) and handspun yarns help makers create a woven fabric with a sett and feel appropriate to the use of the final product. Details of the calculations for understanding and using these numbers are myriad, and it’s easy to get confused.
Instead of going through the arcane details of various counts and their calculations, let’s look at how you may want to use some of these numbers as a handweaver.
Grist
Grist is not a measurement of thickness, per se, but a measure of yards per pound (or meters per kilogram). You will regularly see grists of 250 to 8,000 yd/lb from yarn sellers, while higher grists are more common for very fine commercial weaving and knitting yarns. See Figure 2.
Grist can be estimated from a short length of yarn with the use of a yarn balance, sometimes known as a McMorran balance. This tool uses a very small sample which may or may not be representative of a larger quantity of the yarn. You can determine grist more accurately by directly measuring the full length of a generous amount of the yarn (1 to 2 ounces is sufficient), finding the exact weight of that length with a kitchen or postal scale, and then measuring it with a yardage counter. Divide to find the yards per ounce and convert to yards per pound (yd/lb).
For example, if a put-up of yarn measures 125 yards and the scale tells you it is 2 ounces, the calculation is 125 yd ÷ 2 oz = 62.5 yd/oz; 62.5 yd/oz × 16 oz = 1,000 yd/lb.
Fibers also vary in density, and some spinning techniques create denser yarns than others. For example, a grist of 1,000 yd/lb of worsted-spun yarn in a coarse, strong Lincoln wool will not have the same visual thickness as 1,000 yd/lb of a fluffy woolen-spun merino yarn.
For a given fiber spun with the same spinning technique, the higher the grist (yd/lb), the thinner the yarn.
Wraps per Inch
Measuring wraps per inch (wpi) is a great way to get a good visual “apples to apples” comparison between yarns. It is an estimate of a yarn’s thickness. It’s not quite as scientific as grist, but it is extremely helpful when making a substitution. Instructions for measuring wpi typically sound something like this:
“Wrap the yarn around a ruler or similar device, not too tight, not too loose, with wraps touching but not squished together or overlapping. Wrap for 1 or 2 inches and then count the number of wraps in 1 inch.”
The Halcyon Yarn Sett Tool and the Schacht Dizzy Yarn Gauge are tools to help determine wraps per inch. Photos courtesy of Halcyon Yarn
The Schacht Dizzy Yarn Gauge and the Halcyon Yarn Sett Tool are examples of devices that help with this process, but a simple ruler works, too. Wraps per inch can range anywhere from 2 to 50 or beyond. Although wpi is a number, keep in mind that it is not an exact measurement because it can vary from measurer to measurer.
Wraps per inch is more reliable with yarns that aren’t stretchy. Many knitting yarns are quite stretchy, so the tension put on the yarn during wrapping will have a significant effect on the wpi measurement. On the other hand, many weaving yarns are not stretchy, making their wpi measurements more reliable and therefore more useful.
For weaving, knowing the wpi of your yarns is helpful when determining setts (ends per inch [epi] and picks per inch [ppi]). When planning a warp, a good way to start calculating for a balanced plain weave is to choose setts of about half the wpi. (For a yarn at 24 wpi, you might begin with 12 epi and 12 ppi.) Using this calculation ensures enough room between each warp end to pass an equal-sized weft. For a twill with two warp ends up and two warp ends down, there is 25 to 50 percent more room for the weft to fit, calling for a closer sett of perhaps 16 to 18 epi.
You can also use the wpi measurement to help you think about the feel you want for your finished fabric. A scarf or poncho should be soft with room to loft up and drape easily. This indicates a looser sett and commensurate tension and beat. Upholstery or table linens should be stiffer and sturdier, which would suggest denser setts. In other words, the sett should match the purpose and the feel you want. Use examples of similar grist and wpi in finished projects in Handwoven and weaving books as a starting point and, when in doubt, experiment with a small sample.
Count
Yarns produced for weaving are typically labeled with two numbers in what is often referred to as the “count,” such as 8/2 cotton, 8/2 linen, or 8/2 wool. These yarns cannot be compared directly to each other because the count system is different for different fibers, spinning styles, and manufacturers.
Within each fiber category, one number (usually the smaller one) tells you how many plies or strands of singles are in the yarn: 1 or nothing for a single ply, 2 for a two-ply, 3 for a three-ply, and so on. This number is usually the second number of the designation. The larger number (most often the first number) indicates the “size” of the individual plies used in that particular system or mill. For example, 3/2 yarn would indicate a two-ply yarn in which each ply is a size 3.
Historically, different fibers (linen, wool, cotton) were produced by separate mills, so yarn size was standardized differently for different fibers. That said, size 1 is always the thickest, despite being a different thickness for each category of fiber.
The Weaver’s Companion (see Resources) lists the yardage per pound for size 1 of various fibers: a 1/1 cotton yarn (size 1/singles) would have a grist of 840 yards per pound, for example. Linen, hemp, jute, and ramie have grists of 300 yards per pound at size 1.
Higher counts are multiples of size 1 and have higher grists. For example, a 3/1 cotton has three times the overall grist of singles as size 1 or 1/1 cotton. You can calculate the grist of 3/1 cotton as follows: 3 × 840 yd/lb = 2,520 yd/lb. To calculate the grist of a plied yarn, multiply the count by the size 1 yardage and then divide by the number of plies. For example, a 3/2 cotton has a grist of 3 × 840 ÷ 2 = 1,260 yd/lb.
For a given fiber type, the higher the count, the thinner the yarn, but note that the greater the number of plies, the thicker the yarn.
Confusingly, some sources follow a convention in which cotton and linen have the size first followed by the number of plies, while wool has the number of plies first. In these cases, use your common sense to make a translation to the system you know better, understanding, for example, that Jagger Spun 2/18 worsted wool is obviously a 2-ply not an 18-ply yarn. Also, for cottolin, some companies use the sizing for cotton while others use the sizing for linen, which is why 8/2 cottolin and 22/2 cottolin are the same grist in yards per pound.
“Knitting” Yarns
As weavers, we sometimes want to use exciting softly spun yarns sold as knitting yarns. They are great yarns if you keep in mind how they work and are thoughtful about using them. They can always work as the primary weft in a softly woven piece, such as a scarf, or for a tapestry or as laid-in weft. Soft knitting yarns also excel as pattern wefts in overshot and other weaves tied with a tabby binder; they produce great pattern coverage where more densely spun yarns with similar wpi will not beat in as effectively.
Knitting yarns are more challenging in the warp because they are designed to be soft, squishy, and stretchy and, therefore, may be more loosely spun. In a tightly sett warp, they may shred during warping and weaving unless used cautiously in a reed with large dents. Another issue is the structural take-up that occurs once the stretched and woven warp is released from tension and finished because the piece will tighten as it springs inward—perhaps too much.
To be successful, sampling is the best solution to using unknown or less than obviously suitable yarns you love. Refer to Figure 3.
Alafoss Lopi, Brown Sheep Bulky, Halcyon Yarn Geo, and Maurice Brassard 16/8 cotton, are all approximately the same grist and have close, but not identical, wpi. Each of these yarns has a different hand and density when incorporated in your weaving. The softer-spun Lopi, a “medium-count wool,” is not as dense as the equal-in-grist Geo and Brown Sheep Bulky, but all have greater loft than Brassard’s 16/8 mop cotton.
More recently, the Craft Yarn Council of America created a classification system that is primarily a knitting or crochet reference. We have adapted it here in Figure 4 to include a corresponding range of yd/lb and wpi for each of the seven categories.
Numbers matter, but we urge you not to put too much emphasis on them other than as a means of comparison and a starting point for your own exploration. Your own projects, experiments, and sample notes, or those shared by other weavers, are your best guide for further discoveries and successful projects. Most of all, what matters is the feel of the yarn and fabric in your hands, and there’s no substitute for experiencing those yourself!
Resources
- American Sheep Industry Association, sheepusa.org.
- Babu, Suresh. “Yarn Count, Yarn Fineness, Yarn Number, Yarn Size, Yarn Linear Density, Yarn Ticket Number, Yarn Diameter, Yarn Count Measurement, and Various Yarn Count Systems.” Textile Adviser (blog), October 17, 2018, textileadvisor.com/2018/10/yarn-count-fineness-of-yarn-and-various.html.
- Craft Yarn Council, craftyarncouncil.com.
- Tyler, Amy. “Ask a Spinning Teacher: Numbers.” Spin Off, Fall 2016, 22–24.
- ———. “Debunking the Wraps-per-Inch Myth.” Spin Off, Fall 2010, 32–34.
- van der Hoogt, Madelyn. The Weaver’s Companion. Loveland, CO: Interweave, 2000.
- Yarn Conversion Calculator, servicethread .com/tools.
AMY TYLER lives in Interlochen, Michigan, where she loves numbers as much as she loves spinning and knitting. She still has her college texts on mechanics, calculus, and statistics, and she counts the steps every time she climbs the stairs, but she has a laid-back attitude about numbers and fiber. She is a frequent contributor to Spin Off magazine.
HALCYON BLAKE lives in Bath, Maine, where she operated Halcyon Yarn (originally Halcyon the Weaver’s Friend), which she cofounded in Denver in 1971. She is active in community activities and advises her daughter Gretchen Jaeger and daughter-in-law Rachel Fowler, who are the new generation of owners of the 50-year-old family-run business. She weaves and enjoys the challenges and discoveries of helping fiber artists explore their craft.
