There are so many standards of thread measurement that it’s difficult to keep them straight. The most common methods are weight, denier (DEN yeer) and Tex (weight in grams per 1000 meters of thread).
To simplify this thread confusion, think about thread as light, medium and heavy weight.
Heavy weight threads are Tex 40-90.
Medium weight threads are Tex 27-35.
Light weight threads are Tex 10-24.
When choosing thread, the best method is to use both your eyes and fingers. Look at the thread, feel it, and choose the type that will provide the results you want. Remember that one of the most overlooked properties when choosing thread is not the color. Often it’s the value, i.e., the lightness or darkness, of the thread that’s important. Do you want the thread to ‘pop’ or just to add texture? Trust your senses when you decide.