How to use Ring Size Converter
- Choose inside diameter, circumference or a supported Tiffany reference size.
- Enter the measurement and its unit.
- Compare the reference and confirm fit with the actual jeweller.
Example: Ring Size Converter
Inside diameter 17.3 mm
Options
- Input measurement
- Choose inside diameter, inside circumference or a listed Tiffany reference size. Diameter and circumference are physical measurements; a brand reference is a pinned chart entry.
- Measurement unit
- Millimetres or inches apply only to a physical input. The unit choice is ignored when entering a Tiffany reference size.
Supported inputs and limits
Where your input is processed
This tool processes your input in this browser. Your text and files are not uploaded to UseFreeTools. Check this tool's limits for anything it may save on your device.
A nearest chart row is not a fit guarantee
An inside diameter of 17.3 mm selects Tiffany reference 7 in the pinned table. Ring width, shape and measurement technique can affect fit. The tool does not supply a universal conversion across every brand or decide which size to buy.
Measure the inside dimension
An outside ring diameter includes the band material and is the wrong input. Check your measurement scale and compare the result with the relevant seller chart or an actual fitting. A result outside the pinned table remains outside rather than being extrapolated.
Questions about Ring Size Converter
Does this guarantee a ring will fit?
No. Band width, knuckles, measurement error and the jeweller’s sizing affect fit.
Are these values universal US or international standards?
No. The named dated reference is Tiffany’s chart; other charts can differ.
What happens outside the reference range?
Measurements still convert, but the tool does not extrapolate a ring size.