Thread is measured in several systems. This chart compares the common weight (wt) numbers with the Tex system and typical uses.
| Weight (wt) | Tex (approx) | Common use |
|---|---|---|
| 12 wt | 80 | Heavy topstitching |
| 30 wt | 35 | Bold embroidery |
| 40 wt | 25 | Embroidery, quilting |
| 50 wt | 18 to 20 | Piecing, general |
| 60 wt | 15 | Fine applique |
| 80 wt | 10 | Bobbin, lace |
Two systems, opposite directions. In the wt system a higher number is finer; in the Tex system a higher number is heavier. Do not mix them up when matching thread.
See the Thread Weight Chart and the Seam Allowance Calculator.