You tell a thread's weight from the number on the spool, remembering that a higher number means a thinner thread, and a lower number means a thicker thread (e.g., 100 wt. is fine, 30 wt. is thick). If you see a fraction like 50/2, the first number (50) is the weight, and the second (2) is the number of plies (strands twisted together); the ply number indicates strength, not just thickness.
It is listed on the spool. The important thing to remember about thread weight is that the bigger the number the lighter, or finer, the thread is. Manufacturers measure the length of one gram of thread. If it is 40 meters long, then the thread weight is 40.
A 30-wt. thread is a “heavier” thread, meaning a thicker cross section, because a much shorter thread weighs the same as the 40 wt. In length measurements, higher numbers reflect thicker or heavier threads.
In this case, the 40 wt thread is slightly thicker (heavier) than the 50 wt thread. Note bene: you can tell at a glance which weight you're grabbing from your collection: 40 wt is always on a green spool while 50 wt is always on an orange one.
Weight refers to a thread's thickness. In the world of embroidery and cotton thread, a lower thread weight number is thicker than a higher thread weight.
Tex is the weight (in grams) of 1,000 meters of thread. Or, in other words, 1,000 meters of thread that weighs 1 gm. = 1 Tex. The higher the tex, the thicker the thread.
Fine weight threads run from 60wt to 100wt. These smaller threads are ideal for intricate work such as micro quilting and fine detailed machine embroidery like freestanding designs or monograming. They can be made from cotton on the larger end to polyester on the finer end.
Gutermann Cotton Sewing Thread is a fine 50 weight cotton thread but strong with a silky finish for users who prefer to sew with cotton. Suitable for hand or machine sewing, Gutermann Cotton Thread is a 100% longstaple mercerized cotton sewing thread.
Medium Weight Threads (30 – 40 wt)
This weight is most commonly used in sewing machines for general garment construction, home décor and piecing quilts as it offers strength and subtlety in your stitches. Tip: A universal needle (size 80/12 or 90/14) works well with most projects.
Best Thread Weight for Hand Quilting
For traditional hand quilting, try using 50 wt cotton. It is strong, visible, and glides nicely through the layers. Many modern quilters prefer big stitch quilting for a more decorative look.
The most popular thread used for all types of sewing, quilting, and crafting is a 40 weight thread. When using a 40 weight thread, use a size 80/12 needle. If using a thread finer than a 40 weight, such as a 50 weight, use a smaller needle size such as 70/10.
Commonly used for topstitching, machine quilting, hand quilting, blanket stitch applique, bobbin work, and even 2-strand cross stitch, 28wt gives your projects extra visual impact. It's also a favorite for machine lace and serging decorative edges.
Spend more time doing what you love and less time swapping out spools with Coats & Clarks Professional All Purpose Thread. This 35-weight thread is great for hand or machine sewing, and since it's 100% core-spun polyester, you can use it on all fabrics, be it knits, woven, natural, or synthetics.
Measuring thread using a Caliper and a Pitch Gauge
A very quick and simple option to identify fasteners is to have both a set of calipers and a pitch gauge handy. Simply measure the diameter of the fastener with the caliper, then measure the pitch or TPI with the pitch gauge.
Categorized by a numbering system ranging from 0 to 7, with 0 being the thinnest yarn weight and 7 being the thickest. The weight is determined by measuring the wraps per inch (WPI)—the higher the WPI, the finer the yarn, and the lower the WPI, the thicker the yarn.
For quilting and embroidery thread, the smaller the number, the thicker the thread. The larger the number, the thinner the thread. #40 (40 wt) is much thicker than a #60 (60 wt). Denier: A denier is a unit of measurement that expresses fiber thickness of individual threads or filaments in fabric or textiles.
The “weight” of the thread is normally listed on the side or bottom of the spool. The different thread “weights” are categorized like this – the higher the number or “weight” the thinner the thread; the lower the number or “weight” the thicker the thread.
The higher the number, the finer the thread. So 30 wt. is actually heavier and thicker than 50 wt., and 100 wt. is incredibly fine. Think of it like a seesaw. The heavier (thicker) the thread, the lower the number, and the heavier end tips down.
Such a thin thread is perfect for a variety of techniques, including English Paper Piecing, Hand Applique, Machine Embroidery, Machine Applique, Free Motion Quilting, Free Motion Couching, and more. Needle Recommendations: 70/10 or 80/12 Microtex/Sharp or Embroidery Needle (80wt in the bobbin)
Gutermann 50 WT Natural All-Purpose 100% Cotton Thread | WAWAK.
Medium Weight Threads
These are the types of threads that you will most frequently find, most often 40 or 50wt. They can be used for most construction, quilting, machine embroidery, sergers, and general purpose sewing.
Gutermann 60wt Cotton Thread is ideal for free motion quilting, piecing, heirloom sewing and applique. This thread is great for bobbin fill, machine embroidery lace, quilt bindings, macro stippling, applique.
The Golden Ratio (approximately 1.618) is used in quilting to create visually harmonious designs, guiding decisions on proportions for borders, sashing, and block layouts, often linked to the Fibonacci sequence (e.g., 3, 5, 8, 13-inch strips) to achieve natural balance and aesthetic appeal that feels inherently pleasing to the eye, making quilts look more balanced and intentional. Quilters apply it by multiplying a measurement by 1.618 (or 0.618) to get the next size for elements like borders, or by using Fibonacci numbers for strip widths.
Loose tension can result in an uneven or messy final product, affecting the overall quality and durability of the fabric. When the tension is too loose, the stitches may not hold properly, leading to easily unraveled seams.
Needles sizes #65/9 to #75/11 are your most popular size needles and work well with 60 and 40 weight threads.