What do thread weight numbers mean?

Thread weight numbers describe how thick or thin a thread is. The lower the number, the thicker the thread — and the higher the number, the thinner it is. A 30-weight thread is bold and heavy, while a 60-weight thread is fine and nearly invisible on fabric. Most quilters use 50-weight for everyday sewing, 40-weight for embroidery, and 60- or 90-weight for bobbin work.

Let’s talk thread weight! If you’ve ever been confused by those little numbers on thread spools, don’t worry! You’re not alone. Thread "weight" is simply a fancy way of saying how thick (or thin) your thread is. The general rule is easy to remember: smaller numbers = thicker thread, bigger numbers = thinner thread. (Don't we wish our  bathroom scales worked like that?!) 

For example, a 35-weight thread is thick and bold, perfect for making a statement on your quilt. On the flip side, a 60-weight thread is much thinner and will blend right into your quilt top, like magic!

Thread Weight Guide: What’s It Best For?

30 Weight
This is your go-to for thick, bold stitches. Want to really show off your quilting design? 30-weight thread makes sure everyone notices it!

40 Weight
When it comes to embroidery, 40-weight is the superstar. Most embroidery designs are created with this weight in mind, so it’s kind of the default for that crafty magic.

We are huge fans of Hemingworth and Glide threads, which are 40-weight!

50 Weight
The everyday hero of quilting and sewing. This thinner thread won’t bulk up your seams, which is why quilters adore it! It's also great for machine quilting, and your bobbin loves it too.

Aurifil thread is our go-to thread for all things sewing and quilting!

60 Weight
Another thin option, but even sneakier! 60-weight thread blends into your quilt like it’s playing hide-and-seek. Perfect when you want the fabric to shine more than the stitching. Also a frequent bobbin buddy.

90 Weight
The MVP of bobbin thread for embroidery. It's super thin and often comes pre-wound (yay for convenience!). If you’re working on an embroidery project, chances are you’ll find this on your bobbin.

Picking the Perfect Thread

Choosing the right thread weight is like picking the perfect outfit—sometimes you want to stand out, and other times you want to blend in. Thicker thread means stronger, bolder stitches, while thinner thread lets your fabric and design take the spotlight. So go ahead and mix and match, experiment, and have fun!

Shop Thread at My Girlfriend's Quilt Shoppe

We carry a carefully selected range of threads for quilting, embroidery, and bobbin work — including Hemingworth, Glide, and Aurifil. Browse our thread kits and find the right thread for your next project.

Shop Thread Kits →

Frequently Asked Questions

What does thread weight mean in sewing?
Thread weight refers to how thick or thin a thread is. Lower numbers mean thicker thread, and higher numbers mean thinner thread.

What thread weight is best for quilting?
50-weight thread is the most popular choice for quilting. It's thin enough not to bulk up seams, works well in the bobbin, and is a great all-purpose option for most quilting projects.

What thread weight is best for machine embroidery?
40-weight thread is the standard for machine embroidery. Most embroidery designs are digitized with 40-weight in mind.

What thread weight should I use in my bobbin?
60-weight and 90-weight threads are both common bobbin choices. 90-weight pre-wound bobbins are especially popular for embroidery work.

Is higher or lower thread weight thicker?
Lower numbers are thicker. A 30-weight thread is heavier and more visible than a 60-weight thread, which is fine and lightweight.

What is the difference between 40-weight and 50-weight thread?
40-weight thread is slightly thicker and is the standard for embroidery. 50-weight is thinner and better suited for piecing, quilting seams, and general sewing.

P.S. Not sure which thread to stock up on? Start with a 50-weight for everyday sewing, a 40-weight for embroidery, and a set of pre-wound bobbins — and you'll be covered for most projects. Browse our thread kits at My Girlfriend's Quilt Shoppe and find your new favorites.