Ring Size Chart – US, AU & UK Jewellery Sizing Guide

Finding the perfect fit matters. Use our ring size chart to easily convert between US ring sizes and AU/UK ring sizes. Simply measure the inside diameter of your ring in millimetres and match it to the chart below.

US Ring Size	AU/UK Ring Size	Inside Diameter (mm)
5	J 1/2	15.7
6	L 1/2	16.5
7	O	17.3
8	Q	18.1
9	S	18.9
10	T 1/2	19.8

Tip: If you fall between sizes, we recommend sizing up for the best comfort and fit. All Impermea rings are waterproof, hypoallergenic, and safe for everyday wear.