Ring Blank Sizing


Last updated:  4/26/22, 3/3/17

Nancy LT Hamilton

The Chart

Calculating ring blank size based on interior dimensions

See my page Inside Ring Blank Measurement.  Find your ring size and its interior dimensions or vice versa.

The formula for ID blank sizing

To figure out your own sizing (instead of using the chart) here’s the formula:  (ID + metal thickness) X  pi = ring blank length.  Pi is (3.14159265359+). Some round Pi up to 3.15, or even 3.5 to take into account edge cleanup and other fun things.  Try this first with scrap to see what version of Pi you need to use.  A lot depends on your skills, your tools, and which way the wind is blowing!  Haha.

Add .5mm if the metal used is over 4mm wide.

Need to find out what your gauge is in millimeters or inches? 

See my B&S Gauge Chart

Other Considerations 

How much metal you remove from the ends, how you mark the metal, and how cleanly you cut the metal are all contributing factors to whether we create just the right size, need to stretch our blank, or even find a need to shrink it.  Experimentation is the way to go.  Keep a notebook of what works. Try to be consistent.

Getting a perfectly sized ring is an iffy proposition but, not impossible.  Our ring sizes change throughout the day, month and year – not to mention over a lifetime – some more than others.  Hot weather can increase ring sizes as can water retention, arthritis, medication, salt, alcohol, exercise, etc. So, at any two points in a day, we can have varying ring sizes.

If possible, have your customer measure their finger size over time and under different conditions: during exercise, before and after taking medication, before and after that bag of chips!  This should give you an average to work with.

Want to skip the math and are too tired to look at the chart?  Here’s a Ring Blank Calculator by Mordent Design.

Related Videos

See my YouTube Ring-Making playlist!

Related Web Pages

7 thoughts on “Ring Blank Sizing

  1. Pingback: How to Make a Domed Ring- Part One | Nancy L T Hamilton

  2. Hi Tabitha, Right now, I don’t have time to put up a chart that includes men’s sizes but, here’s the formula: Ring blank length = Inside diameter + metal thickness X 3.14. The funny thing is, I’ve researched this area pretty well, and every chart is different – but, usually by a percent of a millimeter. Even the ring diameters don’t match up. I’ve looked at about 10 different charts. It’s crazy. So, the best I can do, for now – until I have the time to recalculate every size – is to give you the diameters, and have you complete the formula. Here goes (all diameter sizes in mm’s): size 13 1/2 – 22.61, 14 – 23.01, 14 1/2 – 23.42, 15 – 23.83, 15 1/2 – 24.23, 16 – 24.64, 17 – 25.5. That’s the largest I can find for now.

    Here’s an example of the formula for a size 14 ring made from 16 gauge stock: 23.01 (inside dia.) + 1.291 (16 gauge metal thickness -see my drill bit chart, B&S gauge sizes) equals 24.301x 3.14 (pi) = 76.01 ring blank length.

    Hope this helps. Thanks for writing. Nancy

  3. do you have mens sizes I am looking for the measurement for a size 14 and size 22

    Thanks so much,

  4. Hi Beverly, sorry for the slow response. I wrote thick and it should have said wide. Obviously, the chart takes into account metal thickness already. Woops! Thanks for catching my boo boo. I fixed the page to read correctly. Appreciate the heads up! By the way: supposedly (according to Rio Grande), If you don’t have a chart, you are supposed to multiply the ring thickness by PI (3.14) and add that number to the length. Thought you might like to know this just in case your ever stranded on a desert island and want to make a ring. Thanks again, Nancy

  5. one question though, nancy. you mention on this page that if your metal is more than 4mm thick then to add .5mm. however, on your charts page you say to add .5mm if your band is wider than 4mm. do you mean both thicker and wider? wouldn’t the adjustments above account for the band being thicker already? thanks.

  6. thank you! thank you! thank you!!!! i’ve been looking all afternoon for this chart. finally found it as i was starting to fall asleep at my computer ; ) thanks!

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