To the question, “What is thread count?” the number of threads per square inch is the simple answer. Thread count refers to the number of horizontal and vertical threads used per square inch of fabric. This number ranges from 80 up to 1,000 or more. The common belief is the higher the thread count, the better the quality of the sheet, which in most cases is true (although the quality of the thread used has a significant impact!)
When determining the quality of a sheet, you must consider the material from which it is made, the yarn size, and the ply. Yarn size is the diameter of the yarn or thread. The higher the yarn size, the finer the threads. The finer the threads, the higher the thread count will be because more of them will fit in the designated square inch.
Ply is the number of single yarns used in a strand of thread. Single ply means the weaving of fabric is from a single thread. In two-ply fabric, yarns are twisted together before weaving occurs giving the final product twice the thread count. Two-ply fabrics must have a high yarn size (small diameter) so they don’t feel thick.
A thread count of 140-180 is usually a fairly coarse finished product. 200 is good, but a count of 300 to 400 is better. The use of multi-ply yarn in creating high thread count makes a difference in the feel of the resulting fabric.
1,000 is a very high thread count, but may not result in the softest weave. Multiple single threads being twisted together is how such a high thread count is created. This can cause the finished fabric to feel bulky. Generally, a 400+ thread count is the most comfortable for use in bedding.