This page searches oc-ring-legacy-chart-v1, a retailer-style ten-row crosswalk. Use the result as a starting row before physical sizing, not as a universal regional conversion or an ISO 8653 designation.
Ways to enter a size
Choose a direct US, UK, EU, or diameter value; a finger circumference in millimeters; or the inside diameter of a ring in millimeters. The starting direct entry is US 7. The circumference and diameter fields start at 54.4 mm and 17.3 mm.
For a numeric entry, the chart row with the smallest absolute difference is selected. An exact tie keeps the earlier, lower row. There is no interpolation between rows. A UK selection matches one of the ten stored labels directly.
The US 7 row is:
| Stored field | Value |
|---|---|
| US | 7.0 |
| UK | N½ |
| EU legacy crosswalk | 54.0 |
| Inside diameter | 17.3 mm |
| Circumference used for nearest-row search | 54.4 mm |
Entering 54.4 mm as finger circumference therefore returns US 7.0, UK N½, EU 54.0, and 17.3 mm diameter. The EU value is a rounded legacy crosswalk; do not interpret it as exact circumference or a universal national designation.
Measurement-to-purchase workflow
- For a perfectly round existing ring, measure its inside diameter without including the metal.
- For a finger measurement, avoid stretching the string and record millimeters.
- Identify the nearest legacy row, then open the intended jeweler’s own chart.
- Confirm the result with physical sizers, especially across the knuckle.
- Recheck for a wide band, stacked rings, or temperature-related fit changes instead of adding a fixed increment.
Those effects can change fit, but this page intentionally does not apply universal summer, winter, wide-band, or stack adjustments. For another manufacturer-dependent sizing task, the shoe-size formula also requires confirmation against the exact product chart.
Check the chart mode before comparing fit
Save whether you entered a direct size, circumference, or diameter, along with the chosen sizing system. Compare that record with a particular manufacturer’s chart and product information. The legacy chart output can organize your measurement notes but cannot verify fit for every ring design.
Sources
- GIA, Accurate determination of finger and ring sizes — inside measurement for a round ring and chart comparison.
- ISO, ISO 8653:2016 Jewellery — Ring-sizes — Definition, measurement and designation — identifies the separate ring-size designation standard; it does not support these chart rows or certify conformance.