Denier (D) is a unit of measurement used to indicate the mass of a single fiber with a length of 9000 meters. A fiber weighing 1 gram over this length has a linear density of 1D. Higher Denier values indicate thicker, heavier, and more durable fibers.
Fabrics with higher Denier are stronger and more abrasion-resistant but also heavier and stiffer. Lower Denier is softer, lighter, and better suited for comfort-focused applications.
When selecting backpacks, pouches, or clothing, always consider Denier alongside fiber type and fabric construction to ensure optimal performance.