Guide to plug sizes in millimetres

Sizing stretched jewelry causes confusion because maker marks shift between three measurement systems. We machine and carve our plugs and tunnels from 6mm up to 25mm. Understanding how gauge numbers, inch fractions, flares and materials correlate prevents sizing errors when you select your next set of jewelry.

Gauge numbers and small stretched diameters

The standard wire gauge system numbers metal thickness down to 00g before stopping. Our straight barbells and curved navel rings sit at 14G, which measures 1.6mm across the post. As diameters increase, the numbers drop. A 2g plug measures roughly 6mm across the central saddle, while a 0g piece measures 8mm. The largest standard numbered size, 00g, equals 10mm.

Because American wire gauge steps do not align with even metric steps, millimeter measurements provide the most exact fit. A pair marked 0g by one maker might sit at 8.2mm, while another runs slightly small at 7.9mm. We cut our solid pieces to exact metric diameters. Consult your piercer if you need confirmation on your current wearable diameter before purchasing new hardware.

Switching from gauge to inch fractions

Past 10mm, jewelry makers stop using gauge numbers and switch to fractional inches. A one half inch plug corresponds to 12mm across the wearable core. Nine sixteenths of an inch measures 14mm. Moving up the scale, five eighths corresponds to 16mm, seven eighths equals 22mm, and a one inch plug measures 25mm. Millimeters remain the constant reference point underneath these fractions.

A fractional label often rounds to the nearest imperial increment on retail tags. A piece marked one half inch might measure 12.7mm on true imperial scales, but most production body jewelry standardizes this step to 12mm flat. Knowing the metric diameter of your current jewelry lets you match pieces accurately across stone, acrylic, and cast metal designs without guessing.

Single flare versus double flare shapes

The flare is the raised rim that prevents a plug or tunnel from sliding out of place. A single flare piece features one raised lip and one flat edge, secured on the straight end by an o-ring. A double flare piece has raised lips on both ends with a gentle dip, or saddle, in the center. The nominal size describes the narrowest part.

Double flare rims typically measure one to two millimeters wider than the center saddle. A 12mm double flare plug may feature outer edges measuring 13.5mm across. Inserting or removing double flare jewelry requires allowance for that extra lip diameter. Single flare designs maintain a uniform shaft diameter right up to the front rim, making their overall cross section straightforward.

Material density in stone and acrylic

Material choice influences how heavy a large plug feels during daily wear. Natural obsidian and green jade are dense minerals with solid heft in hand. We carve these stones smoothly, but their mass increases noticeably once you pass 16mm. Heavy stone pulls downward, whereas synthetic alternatives carry a fraction of that mass in identical sizes.

Acrylic and silicone sit at the lighter end of the material scale. Clear or colored acrylic maintains a rigid shape without adding drag, which suits larger diameters like 22mm or 25mm. Flexible silicone allows for soft hollow tunnels. Stone options provide a cool, polished surface, while cast polymers offer a light profile for large gauge profiles.

Wearable width between the flares

A diameter measurement tells only half the story of a plug. The wearable width is the usable flat distance along the barrel between the front and back flares. Standard wearable lengths run between 6mm and 10mm. If your lobes are thick, a plug with a short wearable width will pinch because the flares sit too close together.

Thin lobes can cause a wide plug to slide forward and tilt downward unevenly. Single flare tunnels allow some adjustment because you slide the rubber o-ring along the shaft to set the depth. Double flare pieces have a fixed gap between their raised edges. Measure the distance across your best-fitting jewelry to confirm the wearable length before picking a new style.