Here are the main upholstery staple sizes explained and what they are used for:
5/8″ to 1/2″ staples
Used for thin to medium weight fabrics like sheers, broadcloth and chintz. Also suitable for loosely woven fabrics.
9/16″ to 3/4″ staples
For medium weight fabrics like corduroy, gabardine, denim and velvet. This is the most common staple size.
3/4″ to 1″ staples
Needed for thicker, heavier fabrics like leather and vinyl. Also used for double thicknesses of fabric.
1″ to 1-1/4″ staples
Used for very thick, heavy fabrics like outdoor canvas and vinyl-coated fabric. Also suitable for stapling furniture pad to frame.
1-1/4″ to 1-1/2″ staples
For extra thick, staple-resistant materials like vinyl, leather and carpet padding. Also used for layers of fabric plus padding.
2″ staple
Needed for extremely thick materials like foam rubber, thick padding or multiple layers of fabric plus padding.
The sizes indicate the staple length from crown to end of leg. Shorter staples are used for thinner fabrics, while longer staples are needed for thicker materials and padding.