You use 40 weight thread for projects where you want visible, durable stitches that add texture, like machine quilting, embroidery, appliqué, and topstitching, as it offers a good balance of strength and noticeable definition without being too bulky, making it a versatile choice for general sewing and decorative work. It's thicker than 50 wt thread (great for piecing) but finer than 30 wt, providing a lovely "pop" for designs and machine embroidery.
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.
When discussing weight of thread, the smaller the number, the thicker the thread. The weight is determined by how many meters of thread it takes for a skein to weigh one kilogram. In this case, the 40 wt thread is slightly thicker (heavier) than the 50 wt thread.
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. “Denier” refers to the weight in grams of 9000 meters of thread.
60 Weight Thread Offers Digitizers Unique Opportunity
Madeira Classic #60 is approximately 60% finer than Classic Rayon #40. It comes on 1500 meter spools and boasts the same color fastness (to 95 degree washing temperature) as Classic Rayon #40.
70/10 – 100 weight threads. 80/12 – 50 weight threads. 90/14 – 40 weight threads. 100/16 – 30 weight threads and thicker.
50wt Thread
This weight thread is the most popular weight used for piecing quilt tops as it is thin enough to not add bulk to your seams and strong enough to hold them together. It is also used by many for all kinds of quilting including stitch-in-the ditch, straight-line and free motion.
30 wt.: Heavy and Decorative
This is the boldest thread weight you'll typically use for quilting. It creates thick, visible stitches that add texture and dimension to your projects.
The general rule is that if you are using lightweight fabric, use a lightweight thread. If you are using cotton, a middle weight like 40 or 50 wt thread, works very well. Thicker fabrics like denim, may require an even thicker thread.
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.
Here's Why You Shouldn't. Quilting thread is often thicker than regular sewing thread - typically 30 or 40 weight, compared to the standard 50 weight of piecing/normal sewing thread. This extra thickness can impact the accuracy of your seams, especially in intricate piecing, where precision is crucial.
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.
Cotton has a distinct texture and non-reflective matte finish that allows it to blend into the fabric better. It also carries zero stretch to the thread, which is ideal for quilts, as the thread won't cause the quilt to pucker after it's been used or washed.
Picking a hue that has chameleon ability seems to work best for scrappy quilts or quilts with clear light, medium and dark fabric. I like rust, off reds, warm browns, mustard, smoke gray and taupe best. From my experience, these thread colors change as they pass over the quilt to blend rather than distract.
Measuring thread using a Caliper and a Pitch Gauge
Simply measure the diameter of the fastener with the caliper, then measure the pitch or TPI with the pitch gauge. Then simply compare this to a standard reference for fastener sizes to find the proper size.
40 wt thread is a perfect “go to” thread for free motion quilting, embroidery, or binding when you don't want too much bulk in your stitches, but want them to “pop” a little extra!
30 Weight - Thicker and heavier. It covers more surface area in less time. 40 Weight - Thinner and lighter. It is better for finer, more detailed jobs.
The 40wt (brown) cone thread contains 1600 yds of thread. The 50wt (purple) cone has 2000 yds of thread and the 60wt (green) cone has 3000 yds of thread! Yes, the 60wt has almost twice as much as the 40wt thread (3000y v 1600y). Thread weight does make a difference!
A thread is labeled 40 wt. when 40 kilometers of that thread weighs 1 kilogram. A 30 wt. thread is heavier because it takes only 30 kilometers of thread to weigh one kilogram.
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.
Micro threads use needle size 65/9 or 60/8. Again, using a 40 weight thread with a 80/12 needle as a benchmark, if using a heavier thread, move up at least one needle size. If using a 30 weight thread, use a needle size 90/14 or larger.
Gutermann Machine Quilting Thread is fine 50 weight 100% Cotton Thread but strong with a silky luster and is ideal for artists who prefer to sew with cotton. Gutermann Machine Quilting Thread is suitable for machine sewing, and perfect for long arm machine quilting.
Tex 70 is the heaviest commercial size recommended for home sewing machines. Heavier threads make your stitching more visible. The thread size measures the thread's thickness.
Whilst a 40w thread is a popular choice for quilting, I have found that 50w or 60w cotton threads blend into the fabric more successfully, but a 40w polyester thread is my best choice (often called a number 40 when relating to polyester weight) as it is shiny and appears far more like a 50w cotton thread weight.