Enter a size in the system you know and get its equivalent everywhere else, plus the exact circumference and diameter. Values are derived from the official definitions, not copied from a chart.
In France the size IS the finger circumference in millimetres. A 52 measures 52 mm.
A ring size is a measurement, not an exact value: ISO 8653 allows tolerances, and a jeweller can usually resize by about two sizes either way depending on the design.
Compare three online size converters and you will often get three answers half a size apart. That is not inevitable — it is a method problem.
Two reliable methods, and the mistakes that skew the result.
On national systems, measuring, and its limits.
In France, a woman's ring finger most often falls between 50 and 54, a man's between 60 and 62. These are orders of magnitude only: hands vary far more than the averages suggest, and a ring meant as a gift is always better chosen from a measurement than from a statistic.
Because they confuse the French system with one where the size equals the circumference minus 40. In France the size is the finger circumference in millimetres: a 52 mm ring is called size 52, never size 12. The error is widespread in international conversion charts.
A diameter, that is 53.4 millimetres around the finger. Both conventions coexist in Germany, but they never overlap: the diameter of a worn ring falls between 15 and 22 millimetres, a circumference between 47 and 69. The order of magnitude is therefore enough to tell which is meant.
Usually yes, by around two sizes in each direction, but it depends entirely on the design. A plain band is easy to alter; a full eternity ring, a continuous pattern, or a piece in titanium or ceramic cannot be resized, or only poorly. Ask before you buy.
They are calculated from each system's official definition, always going through the inner circumference, rather than copied from an existing chart. The formulas and their checks are documented in the tool's source. That is why small differences appear against other converters, many of which inherit successive roundings.
In Liink the size travels with the order, from the request through to the workshop sheet. Your manufacturers see the size you ordered, with no re-entry and no rough conversion.
From €99/month • Free for your manufacturers • No credit card