Ring size is a measurement used to denote the circumference of jewellery rings.
There are several systems for denoting the sizes of jewellery rings in use around the world:
The ISO standard for ring sizes is ISO 8653:1986, 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.US, Canada, Mexico: ring_inside_circumference = 36.5 mm + 2.55 mm × ring_sizeUS, Canada, Mexico: ring_diameter = 11.63 mm + 0.8128 mm × ring_sizeRing sizes can be measured physically by a plastic or metal ring sizer, or by measuring the girth 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.
