What is Fabric Denier?

Posted by Mark Richardson on Nov 09, 2022

What is Fabric Denier?

Wherever fabrics are used in the production of outdoor gear, be it tents, sleeping bags or waterproof jackets, the specification for the product often refers to the fabric being 10D, 50D, 30D etc, where the D refers to the Denier of the fabric.

Fabric Construction

Fabric is made by weaving together threads of various materials such as nylon, polyester, cotton or silk to produce a ‘mat’ of fabric. Each thread though is made up of individual fibres or filaments which are wound together to make a length of thread.


Denier is used to refer to the thickness of the thread used in the construction of the fabric. A higher Denier refers to a thicker thread.


Although the above is correct the strict definition of Denier is actually a measure of the weight of 9000m of the thread, this is done using a single strand of silk as a reference point, where a single strand of silk 9000m long weighs 1 gram. The silk therefore has a Denier of 1.


Because it’s a measure of weight used as an indicative guide to thickness the relationship between different Denier’s is not straightforward, for example the thickness of a 40D fabric is almost 1.5 times the thickness of a 20D fabric (not twice as you might expect).

Use of Denier

Threads with a Denier of less than 1 are referred to as Microfibres. A human hair is typically 20D for reference.


Denier is often quoted alongside Thread Count, which is the sum of the vertical and horizontal threads per square inch of fabric, therefore an assessment of the strength and/or abrasion resistance of a fabric would require knowledge of the actual thread material (Nylon, Polyester etc.. ) its Denier and also the thread count achieved in the manufacturing process. In addition fabrics generally have coatings applied to them such as Silicone and Polyurethane for waterproofing, DWR coatings (Durable Water Repellency). Coatings can also affect the durability, strength and UV resistance of fabrics.


This all means that even though you would expect higher Denier fabrics to be stronger and more durable than lower Denier fabrics this is not always the case, although a big difference will indicate a stronger and more durable fabric.

Mark Richardson

Mark was the founder of Ultralight Outdoor Gear back in 2006 and has completed long distance backpacking routes in some of the remotest parts of the world. His favourite hikes have been Torres del Paine (full circuit), the John Muir trail and the Markha Valley trail (Ladakh, India). Although semi-retired Mark has not lost any enthusiasm for minimalist backpacking and is tackling Scotland’s Munros choosing multi-day backpacking routes over the more usual guide book excursions.

Read more from Mark Richardson

Fabrics used in Outdoor Clothing and Equipment are often described as 20D or 7D, this figure is known as the Denier of the fabric and is useful in determining the differences between some products. On this page we explain what it means and how it can be used.