The most common embroidery weight thread is 40 wt. That is suitable for most embroidery designs because digitizers typically create designs to be stitched with 40 wt. thread. The smaller the number, the heavier the thread. The higher the number, the lighter the thread. Common thread weights are 30 wt., 40 wt., and 50 wt.
Sometimes when designs are too dense, you can try using a lighter 50 wt. thread. That is the weight of most standard sewing threads.
Bobbin threads are generally finer and are often 60 wt. or even 100 wt.
A heavier 12 wt. cotton would simulate hand stitches in heirloom embroidery or when stitching triple stitch and redwork or linework designs. Delicate heirloom stitching may require a very fine 100 wt. thread.
Weight (in grams) of 9000 meters of thread. A larger number indicates heavier thread. A number such as 120/2 equals two strands of 120 denier thread for a total of 240 denier. Most embroidery thread has a denier measurement. However, this measurement traditionally applies only to synthetic threads. Comparative note: a 40 wt. thread is approximately 240 denier.
Weight (in grams) of 1000 meters of thread. 40 wt. = 240 denier = tex 25.