Ifyou’d like to measure your partner’s ring size secretly, we suggest measuring a ring they already wear. Find the right ring size with our free sizing tool. Get tips on how to Howto find your ring size. Use the dropdown menus below to help find your circumference or diameter measurement. Next, use the chart to see which ring size corresponds to Ifa woman typically wears rings with sizes between 5-7, then they will need one around this range as well. Some customers ask how to measure ring size in cm, you simply need to divide the millimeter by 10 for the ring size chart conversion. So 4 millimeters is 0.4 cm and vice versa, 0,5 centimeters is equal to 5 millimeters. RingSize Conversion. Ring size conversion table between American (US), UK, Australian, Canadian, Japanese and Chinese ring sizes including the diameters in inches and millimeters (mm). To view all size conversion tables, please visit size conversions. Getan accurate ring size chart of 2.25, 2.5, 2.75, and 3 inches right here! Summary. The ring size chart below is the easiest way to convert between inches and ring sizes. Here’s a quick summary of the most popular sizes: See how many inches or centimeters the marked piece of string is. Convert to millimeters. Make sure to get the Alternatively you can purchase a Korean ring size gauge set (including a ring gauge and ring sizing strip) for approximately KRW 5,000. Simply include it in your package when shopping with us. These gauges weigh about 50-100g, so they won't affect your package weight or shipping fee. OuraRing Size conversion chart in mm and centimeter. The below Oura ring size guide convert ring measurements in millimeter (mm), centimeters (cm) of the inner diameter into a official Ring size by Oura. 1mm = 0,04″, meaning an Oura ring size 8 equals a 0.74″ inner diameter. Mens Rings Girls' Rings Boys' Rings Use our Ring Size Calculator to find your correct size easily. Shop Fashion Deals at Ring Size Chart For adults and children. Note: U.S. kRatY.