Choose two brands to see their native sizing systems and fit notes side by side. Use the comparison to choose the right starting measurement, then confirm with the official brand guide before ordering.
These brands use different native sizing systems. Convert the measurement first, then confirm the collection guide before ordering.
Cartier rings (including the Love and Trinity) are sized in EU/ISO numbers, usually 48–62. Cartier 50 ≈ US 5½, 52 ≈ US 6, 54 ≈ US 7, 56 ≈ US 7½.
Tiffany sizes are standard US numbers. Use your measured US size directly; for international Tiffany boutiques, convert to EU (circumference in mm) with the tool above.
Brand systems and fit notes are a starting point, not a guarantee. Collection, band width and finger changes can affect fit.
Ringsizely is independent and is not affiliated with, endorsed by, or sponsored by the brands named on this page. Brand names are used only to identify sizing systems; confirm the current size guide with the retailer before ordering.
Both use EU/ISO-style labels, so their size numbers begin from the same circumference-based scale. Collection and band shape can still change the final fit.
Convert the US size to the EU/ISO equivalent, then use the official brand guide as the final ordering check.