Ring size - wikipedia Ring size For the `` ring gauge '' used for cigars ( 1 / 64 inch ), see Cigar. This article has multiple issues. Please help improve it or discuss these issues on the talk page. ( Learn how and when to remove these template messages ) This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( January 2014 ) This article possibly contains original research. Please improve it by verifying the claims made and adding inline citations. Statements consisting only of original research should be removed. ( January 2014 ) A Bergeon ring sizing stick. ( ISO 8653 : 1986 and number scales ) Ring size is a measurement used to denote the circumference of jewellery rings. Contents 1 Systems 2 Equations 3 Chart 4 References Systems There are several systems for denoting the sizes of jewellery rings in use around the world : The ISO standard for ring sizes is ISO 8653 : 2016, which defines standard ring sizes in terms of the inner circumference of the ring measured in millimetres. In the United States and Canada, ring sizes are specified using a numerical scale, with quarter and half sizes. An increase of a full size is an increase of 0.032 inch ( 0.8128 mm ) in diameter, or roughly 1 / 10 inch ( more precisely, 0.1005 in or 2.55 mm ) in inside circumference. In Ireland, the United Kingdom and Australia, ring sizes are specified using an alphabetical scale, with half sizes. In India, Japan and China, ring sizes are specified using a numerical scale, that only has whole sizes, and does not have simple linear correlation with diameter or circumference. In Austria, France, Germany, Belgium and Scandinavia, ring sizes are specified using actual internal circumference in mm ( the same as the ISO standard ). In some countries, half sizes may be used. In Italy, Spain, Netherlands, and Switzerland, ring sizes are specified as the circumference minus 40mm. A 50 in Germany will be a 10 in Switzerland. Before accepting the equations and values in the article, consider the multiple dissenting opinions listed in the talk page and other sites. For the system prevailing the United States, the Circular of the Bureau of Standards summarizes the situation as : `` While there apparently is only one standard in use in the United States, in reality, because of the lack of specific dimensions and because of the errors introduced by the adoption of a common commercial article as a pattern, there are many, although similar, standards. '' There does not appear to have been any improvement in the standard since then. Equations To convert from US, Canada and Mexico ring sizes ( s ) to ISO 8653 : 2016 circumference : c = 2.55 × s + 36.5 ( displaystyle c = 2.55 \times s + 36.5 ) and for diameter : d = 0.8128 × s + 11.63 ( displaystyle d = 0.8128 \times s + 11.63 ) Chart Conversion chart for ring sizes Inside diameter Inside circumference Sizes ( in ) ( mm ) ( in ) ( mm ) United States, Canada and Mexico United Kingdom, Ireland, Australia, South Africa and New Zealand China, Japan, South America India Italy, Spain, Switzerland 0.458 11.63 1.44 36.5 0 0.466 11.84 1.46 37.2 1⁄4 0.474 12.04 1.49 37.8 1⁄2 0.482 12.24 1.51 38.5 3⁄4 A1⁄2 0.49 12.45 1.54 39.1 0.498 12.65 1.56 39.7 11⁄4 B1⁄2 0.506 12.85 1.59 40.4 11⁄2 0.5 0.514 13.06 1.61 41 13⁄4 C1⁄2 0.522 13.26 1.64 41.7 1.75 0.53 13.46 1.67 42.3 21⁄4 D1⁄2 2.25 0.538 13.67 1.69 42.9 21⁄2 0.546 13.87 1.72 43.6 23⁄4 E1⁄2 3.5 0.554 14.07 1.74 44.2 4.25 0.562 14.27 1.77 44.8 31⁄4 F1⁄2 5 5 4.75 0.57 14.48 1.79 45.5 31⁄2 5.5 0.578 14.68 1.82 46.1 33⁄4 G1⁄2 6 6 6 0.586 14.88 1.84 46.8 7 6.75 0.594 15.09 1.87 47.4 41⁄4 H1⁄2 7 7.5 0.602 15.29 1.89 48 41⁄2 8 8 8 0.61 15.49 1.92 48.7 43⁄4 9 8.75 0.618 15.7 1.94 49.3 5 J1⁄2 9 9.25 0.626 15.9 1.97 50 51⁄4 10 10 0.634 16.1 1.99 50.6 51⁄2 K1⁄2 10 10.5 0.642 16.31 2.02 51.2 53⁄4 11 11.25 0.65 16.51 2.04 51.9 6 L1⁄2 11 12 11.75 0.658 16.71 2.07 52.5 61⁄4 12 12.5 0.666 16.92 2.09 53.1 61⁄2 M1⁄2 13 13 13.25 0.674 17.12 2.12 53.8 63⁄4 13.75 0.682 17.32 2.14 54.4 7 N1⁄2 14 14 14.5 0.69 17.53 2.17 55.1 71⁄4 15 15 0.698 17.73 2.19 55.7 71⁄2 O1⁄2 15 15.75 0.706 17.93 2.22 56.3 73⁄4 16 16.25 0.714 18.14 2.24 57 8 P1⁄2 16 17 17 0.722 18.34 2.27 57.6 81⁄4 Q 17.5 0.73 18.54 2.29 58.3 81⁄2 Q1⁄2 17 18 18.25 0.738 18.75 2.32 58.9 83⁄4 19 19 0.746 18.95 2.34 59.5 9 R1⁄2 18 19.5 0.754 19.15 2.37 60.2 91⁄4 20 20.25 0.762 19.35 2.39 60.8 91⁄2 S1⁄2 19 21 20.75 0.77 19.56 2.42 61.4 93⁄4 21.5 0.778 19.76 2.44 62.1 10 T1⁄2 20 22 22 0.786 19.96 2.47 62.7 101⁄4 U 21 23 22.75 0.794 20.17 2.49 63.4 101⁄2 U1⁄2 22 23.25 0.802 20.37 2.52 64 103⁄4 V 24 24 0.81 20.57 2.54 64.6 11 V1⁄2 23 25 24.75 0.818 20.78 2.57 65.3 111⁄4 25.25 0.826 20.98 2.59 65.9 111⁄2 W1⁄2 24 26 26 0.834 21.18 2.62 66.6 113⁄4 X 26.5 0.842 21.39 2.65 67.2 12 X1⁄2 25 27 27.25 0.85 21.59 2.67 67.8 121⁄4 Y 28 27.75 0.858 21.79 2.7 68.5 121⁄2 Z 26 28.5 0.866 22 2.72 69.1 123⁄4 Z1⁄2 29 29 0.874 22.2 2.75 69.7 13 27 30 29.75 0.882 22.4 2.77 70.4 131⁄4 Z1 30.5 0.89 22.61 2.8 71 131⁄2 31 31 0.898 22.81 2.82 71.7 133⁄4 Z2 32 31.75 0.906 23.01 2.85 72.3 14 Z3 32.25 0.914 23.22 2.87 72.9 141⁄4 33 33 0.922 23.42 2.9 73.6 141⁄2 Z4 33.5 0.93 23.62 2.92 74.2 143⁄4 34 34.25 0.938 23.83 2.95 74.8 15 35 34.75 0.946 24.03 2.97 75.5 151⁄4 35.5 0.954 24.23 76.1 151⁄2 36 36.25 0.962 24.43 3.02 76.8 153⁄4 36.75 0.97 24.64 3.05 77.4 16 37 37.5 Ring sizes can be measured physically by a plastic or metal ring sizer, or by measuring the inner diameter of a ring that already fits. There are also online measuring tools available. Online measuring tools vary, but many offer multiple ways to measure the ring size, such as wrapping a paper cutout around the finger, or measuring a current ring according to a chart. References Jump up ^ `` Jewellery -- Ring - sizes -- Definition, measurement and designation ''. Jump up ^ `` The Official International Ring Size Conversion Chart ''. Jump up ^ `` Larson Jewelers Common Ring Sizing Systems of the World ''. Jump up ^ S.W. Stratton, Director ( Jan 24, 1921 ). Circular of the Bureau of Standards, No 43., Jewelers ' and Silversmiths ' Weights and Measures ( Report ). United States Department of Commerce. p. 39. Jump up ^ `` Convert Your Ring Size to MM : Ring Size Guide ''. Jewelove. Retrieved 2016 - 11 - 27. Retrieved from `` https://en.wikipedia.org/w/index.php?title=Ring_size&oldid=818197992 '' Categories : Rings Sizes in clothing Hidden categories : CS1 : Julian -- Gregorian uncertainty Articles needing additional references from January 2014 All articles needing additional references Articles that may contain original research from January 2014 All articles that may contain original research Articles with multiple maintenance issues Talk Contents About Wikipedia Français Tiếng Việt Edit links This page was last edited on 2 January 2018, at 05 : 00. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: what is a size 9 ring in mm
Answer: 18.95