Spreadsheet based tool to help convert between the various ring size system (e.g. US+Can, UK+IE+AUS+NZ, IND+CHN, Swiss)and allow you to calculate the ring internal diameter in mm. Also gives linear best fit equations based on data found here http://en.wikipedia.org/wiki/Ring_size

Potentially very useful when combined with the following: Ring Creation Script thingiverse.com/thing:12448 Diamond size shape weight conversion Spreadsheet thingiverse.com/thing:12586 Ring metal cost calculator thingiverse.com/thing:12589 for costing a custom engagement ring or other such tomfoolery.

Note: A table allowing you to convert between all the different sizing systems is now provided. These converted values are provided as indications only!!! If a size doesn't exist in a system it rounds up to the next available size. Also beware of very small or large sizes as the different systems don’t start and end ant the same points. Check with a professional/the wearer before committing your time/money/etc. to an actual ring. I take no responsibility for incorrectly entered values, erroneous formulae, changes in finger size over time, weight gain/loss or the weather.

0. Find a ring that fits and using a callipers or a jewellers ring gauge get the size and sizing system
1. Use equations on Graph or provided conversion table to convert between sizing systems
2. Use results from equations to generate a ring in your favourite CAD tool
3. Print/Laser cut/Cast/Forge etc.
4. ???
5. Present your perfectly fitting custom ring to your intended