The right jewellery size depends on your piercing placement, anatomy and preferred fit, so there isn't one standard size that will suit everyone.
For labrets and barbells, the two main measurements are the gauge and bar length. Gauge refers to the thickness of the bar that passes through your piercing, while bar length determines how the jewellery sits within the piercing.
For clickers and hoops, you'll usually need to consider the gauge and inner diameter. The inner diameter is the measurement across the inside of the hoop and affects how closely the jewellery sits around your ear or piercing.
If you're replacing jewellery that already fits comfortably, checking the measurements of your existing piece can help you choose the same size. Even a difference of 1–2mm can noticeably change the fit.
If you're unsure which size you need, we recommend asking a professional piercer who can assess your anatomy and piercing placement in person.
For more detailed sizing advice, see our Barbells & Labrets: Sizing, Fit, and Tips and Clickers & Hoops: Sizing, Fit, and Tips guides.