Diamond Petite Flower Flat Back Earring

How to size a flat back stud

A flat back stud has a decorative top that threads onto a post ending in a smooth, flat disc. The disc rests against the back of the piercing so it sits flush, won't snag, and stays comfortable enough to sleep on. Two measurements make it fit right: gauge (post thickness) and length (post span).

Gauge — the thickness of the post

Gauge is how thick the post is, and it should match what your piercer used so the stud seats securely without shifting. The scale runs in reverse — a smaller number is a thicker post, so an 18G post is thinner than a 16G. Most flat back ear and nostril piercings use 18G or 16G.

Length — the post that spans your piercing

Length is the distance from the flat disc to the front of the stud — the part that passes through your piercing, measured without the decorative top. While healing, a little extra room (often 8mm) leaves space for swelling; once healed, a shorter post (6mm or 5mm) keeps the top sitting close and flush. Too long and the top spins or catches; too short and the disc presses in.

Not sure? Match the gauge and length on jewelry that already fits you, or check with your piercer.