Untangling Thread Sizes

I assumed thread sizing was straightforward.  I was wrong.

As it turns out, there are several classification systems. 

To assist myself, I compiled a very simple list of thread classification, sizes, and general use.  This by no means is an exhaustive list of all the different variants of thread sizing systems but just a few basic guidelines.

There are two distinct classes for thread classification:

Fixed Weight and Fixed Length

Fixed Weight	Fixed Length
Thread count/size is expressed based on fixed weight	Thread count/size is expressed based on fixed length
Number of 1-meter (Metric) or 840-yard (English/Imperial) lengths of yarn called hanks in either a Kilogram (Metric) or 16 Ounces (English/Imperial)	Size indicated by the weight of a fixed length of yarn
Thick yarns = low count/size Thin yarns = high count/size	Thin yarns = low count/size Thick yarns = high count/size
Example: Ticket system	Example: Tex system

Here's how to put those sizes into use:

Application	Heavy Weight	Medium Weight	Light Weight	Lighter-Weight
Use	Topstitching, Buttonholes, Heavy Duty	Seam Construction for Most Applications	Overlock, Knits, Very Lightweight Fabrics	Blind Hem
Ticket System* ("Weight")	30-40	60-80**	130-140	180-200
Tex System	60-100	30-40	20-27	5-15

*Note: The term 'ticket system' means a whole lot of different  things and is also called Metric System and often referred to as 'Weight' (e.g. "Use 30-weight thread for this project"). It may be further subdivided depending on fiber content (cotton, polyester, rayon, silk, etc.) and even those are further subdivided depending on how the thread was made, number ply, etc.

**70 most common for spun polyester
**50 or 60 most common for cotton

To add a bit more fun……there is another weight-based system called ‘Denier.’ The thread size/count is based on the weight, in grams, of 9000 m of yarn. If a given length weighs 100 grams per 9000 m of yarn, it would be classified as 100 denier. A 100-denier thread is thicker than a 50-denier thread. (Just thought I would toss this out there while on the subject.)