Nose piercing is usually done with an 18 gauge (1.02mm) post. After a nose piercing heals, most people switch to a 20 gauge (. 81mm) post because it is thinner and leaves a smaller hole. A post thinner than 20 gauge is not recommended for most nose piercings.
Moreover, is 18G bigger than 20G nose ring?
The thickest Gauge is 18 Gauge. This would be your choice if you have recently had your nose pierced or wear that gauge normally. 20 Gauge is thinner than 18G and is the standard most popular size.