Thread Weight 101

Picture this:  you’re standing in a quilt shop searching for thread for your next project.  There are approximately 50,000 spools (or so it seems) to choose from.  Every color of the rainbow is available but the spools also have different weights and numbers on them.  What is thread weight?  Why does it matter?  Feeling overwhelmed?  Don’t be!  Thread weight is easy to figure out.

What is Thread Weight?

All threads have a weight.  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.  If they measure another thread and it takes 80 meters of it to equal one gram, then that thread is 80 weight.  If they measure even another thread and it takes only 12 meters of it to equal a gram, then that thread is 12 weight.

So Many Choices!

Thread weight can vary greatly, that’s for sure.  You may see thread weight as low as 3 and as high as 100.  The threads with low numbers, like 3 or 12 (which is more common than 3) will work well for embroidery.  They are very thick. Check out these 12 wt. fabrics.  The thread that is 100 weight is going to be very fine, almost like hair.  It’s easy to compare thread to spaghetti noodles.  When shopping for spaghetti noodles, you can buy thick cut spaghetti or fine angel hair noodles. 100 wt thread is the angel hair pasta of the thread world.

When sewing, how do you know what thread weight to use?  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, works very well.  Thicker fabrics like denim, may require an even thicker thread. It’s a good idea to keep several different weights nearby, just to play around with.  You will quickly see the difference and that will make it much easier to decide on thread for that next project.

The next time you’re standing on that thread aisle, you will have a better understanding of thread weight.  Happy sewing!