There are two considerations to take into account when finding a nose ring hoop size: the ring’s gauge and the inner diameter. The gauge refers to the thickness of the hoop, with a lower gauge number meaning a thicker nose ring. The inner diameter means the distance between one side of the hoop to another. Most people fall between a 5mm and 7mm diameter and work well with an 18-gauge hoop—although every nose is unique and your personal size preference may vary.
If you don’t remember previous hoop sizes that you liked or if this is your first nose ring hoop experience, you can determine the gauge by asking your piercer, who may use a micrometer, caliper, or gauge cards to size you. For the most accurate size, ask them to measure the inner diameter as well or, if you have your hoop already, you can calculate it at home. To do this, measure a straight line through the inside of the hoop from end to end by drawing a line on paper or tracing around the hoop and measuring the diameter for a close estimate.