For those of us that find math formulas daunting, let me say chainmaille math - not hard. You don't need to try to convert fractions to mm to decimals and the AR calculation is nothing but elementary multiplication and division. Once you have the number from the calculation - the rest of the task is simply matching the number you came up with to a chart. Sincerely, if I can do it - you can do it.

First thing - use google to find a chart that lists side by side equivalent numbers i.e., columns of fractions, decimals & mm. The internet is full of these charts and they are easy to find. You don't need an exhaustive chart just one that goes up to an inch.

One line from a comparison chart will read: 5/32, 0.1563, 3.9688 - all those numbers are equal, just in different forms. Also, find a chart that list the different wire gauges that you will use to calculate AR. Again the internet is full of charts that list wire sizes i.e., 16awg = 1.29mm, 0.05 or, if you use 16swg = 1.63mm, 0.06mm. You don't need an exhaustive list - just the sizes of wire you use - my list goes from 20g - 8g. If you only like using 24g - 18g, just get those numbers.

Secondly, always stay in the same unit of measure to do the AR calculation. It doesn't matter if you use mm or decimals - it doesn't even matter what type of mandrels you have at this point.

Using the numbers you know, do the AR calculation; taking Mollie's numbers from the example above, the rings she needs to make her necklace are 10.07mm ID rings. Since there probably isn't a 10.07mm mandrel, she could look at a chart with the equivalent numbers (fractions, decimals or mm), and see she could use a 10mm mandrel, or go down slightly more to use a 25/64ths (9.92mm) mandrel or go up slightly to 13/32ths mandrel (equals 10.31mm).

All that needs to be done once you have the calculated number from the AR formula is matching the numbers e.g., 10.07mm (from Mollie's AR calculation) to the closest mandrel in the set available to you - imperial or metric.

Let all your old math 'baggage' go - AR is not hard.

Right on Karen!

I am SO not a math person, but chainmaille (and jewelry math in general) hovers in the 7th grade math range so it's ok with me. I teach chainmaille and have several resource sheets (as word documents) for my students with the charts that Karen suggested. Send me a message if you'd like me to email them to you.

Mollie

I am so thankful all of you answered my post. I coated my tools yesterday, let them dry and started on one of the bracelets today. I actually found doing the pattern very easy. My tools are horrible right about now. They are two different sizes which makes it feel a little akward. I like the coating on the tools because it has helped keep the rings from maring, which I know I would have done without it. The coating makes one pair of pliers a little off (not leveled). Right about now my thumbs are a little sore and wrists a little tired so I decided to quit for the night. I did get about five inches done. Even though it was a little akward I just had to start that bracelet. I already know I like it. I'm ready to invest in a set of Lindstrom pliers. I posted yesterday asking about using dead soft wire and tumbling. I think the dead soft would be a little easier on my fingers and wrists. So, you know where that took me. I thought okay, I don't want to have to hand cut all my jump rings so now I'm thinking about a Koil Kutter. Now, you know you just have to have everything you can afford to buy. I'm convincing myself to just slow down and finish the bracelets first. I'm a quarter of the way there.
When this forum changes I hope I can still find all of you. You have been a great help. I know I'm going to need your help in the future.
Thanks, Donna