Ring size


Ring size is a measurement used to denote the circumference of jewellery rings and smart rings.

Measure

Ring sizes can be measured physically by a paper, plastic or metal ring sizer or by measuring the inner diameter of a ring that already fits.
Ring sticks used to measure the inner size of a ring can be made from a variety of materials including plastic, delrin, wood, aluminium, aluminium with wooden handle and so on. Digital ring sticks also exist.

ISO sizes

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. ISO sizes are used in Austria, France, Germany, Belgium and Scandinavia, as well as some other countries in Continental Europe.
This international standard specifies a method to measure the ring-size using a ring stick with defined characteristics, which is mainly used during manufacturing steps, and specifies the designation of the ring-size.
For jeweller-consumer relationships, the finger size is measured with a finger gauge set made up of a ring for each size with the same diameter and tolerance as the ring stick ones. The sizes are in millimeters and correspond directly to the outer circumference of the ring stick to the inner circumference of the finger gauge.
Internal ring circumference 495051525354555657585960616263646566676869707172
Internal diameter 15.615.916.216.616.917.217.517.818.118.518.819.119.419.720.120.420.721.021.321.622.022.322.622.9

Other traditional and regional systems

There are several systems for denoting the sizes of jewellery rings in use around the world:
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." The standards are generally consistent and remain so. There does not appear to have been any improvement in the standard since then.

Chart for size conversions

Equations

To convert from US, Canada and Mexico ring sizes to ISO 8653:2016 circumference:
and for diameter:

Resizing a ring

Most rings can have their size adjusted to some extent. There are various methods which may be suitable depending on the complexity of the ring and material used. For example, rings of soft material may be opened somewhat using a special form of punch. In other cases the ring may need to be cut open and material either added or removed, before fusing the ring together again. All other factors being equal, sizing a ring up will cost more than sizing a ring down; sizing up requires the jeweler add precious metal, sizing down allows them to remove it.

Sizing beads

Sizing beads are an alternative way to reduce the functional ring size by adding small metal beads to the inner surface of a ring, and can aid in holding the ring in place against the finger. Mounting sizing beads can be an easy way to resize a ring that is too big. They are also sometimes used on very top heavy rings as a counter balance. Persons who have knuckles that are much larger than their finger base may also benefit from sizing beads to keep a ring from spinning. Sizing beads are typically made of the same metal as the rest of the ring, since it is easier to solder two similar metals.