United Kingdom (letters)
JewelryWiki Editorial·1 source·Reviewed 2026-08-04
Sizes written as letters rather than numbers — and as of 25 March 2026 the British Standard that defined them is withdrawn. No replacement is recorded in BSI’s catalogue under that designation.
Properties
| Property | Value | Authority |
|---|---|---|
| How a size is written | Letters rather than numbers. The technical content — which letter corresponds to which circumference — sits inside BS EN 28653:1993 and its predecessors, which BSI sells rather than publishes, so it is NOT reproduced here. See the note. [1] | — |
| Standard status | WITHDRAWN. BSI records BS EN 28653:1993, “Jewellery. Ring-sizes. Definition, measurement and designation”, as published 15 March 1993 and withdrawn on 25 March 2026. That standard was the British and European adoption of ISO 8653:1986 — the first edition, which ISO itself cancelled and replaced in 2016. So the British designation that the trade still uses daily rests on a withdrawn adoption of a superseded edition. [1] | — |
| Defining body | BSI, as the British adoption of a European adoption of the ISO standard. [1] | — |
| What to watch for | THIS SITE PUBLISHES NO LETTER-TO-MILLIMETRE CONVERSION TABLE, and the reason is the reason this collection exists. That table is behind BSI’s paywall, and every freely available version traces back to trade sites or to a Wikipedia article that carries an “original research” maintenance banner. A conversion chart whose provenance stops at another website would be the most-used wrong answer on this site, because a ring bought one size out is a ring that does not fit. If you need a UK size converted, have it measured on a gauge rather than read off a chart — and ask the jeweller which standard their gauge is cut to. [1] | — |
Sources
- BSI Knowledge — catalogue entries for ISO 8653:2016 and BS EN 28653:1993 — British Standards Institution (BSI Knowledge, standard status records)