The list below is just to be interpreted as a general guidance, and not as an strict rule on what coin ring size can be made from any specific coin. Actual coin ring size can be expanded one size larger or smaller than listed. Normally large thick coins will produce coin ring that will look very big and bulky on medium and small hands, but sometimes this is what the person likes. It all comes down to personal preference. The opposite of this, a coin ring made out of small coin will need to be stretched to fit on large side hands. Small ring on big thick hands may look visually unbalanced, but in conclusion, there is not one specific good look of a coin ring on a hand. Remember, beauty is on the eye of the beholder.
On last important note to remember is that all coin rings have an inherent characteristic, and that is that the inside band is not straight and has a slight taper. This will make your coin ring to measure one size larger than the other. About 1/4 to 1/2 half size smaller on the reed side. This happens because the inside where the hole is made) is normally thinner then the outside reed of the coin. More over, because the inside section is stretched more during the forging of the coin ring. Because of this, the true ring size of a coin ring is the one taken from the reed side of the coin ring, and not the cut side which will always be slightly wider than the reed side.
Actual coin width and thickness (edge) is given to help you have some reference how big or thick coin ring will look.
US Quarter
Coin Width = 24.26mm (0.455 in.)
Coin Thickness (edge) = 1.75mm
Weight = 5.67g
Recommended ring size range (us) = 4 thru 11
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US Small Dollar
Width = 26.49 mm (1.04 In.)
Thickness (edge) = 2.0mm
Weight = 8.1g
Recommended ring size range (us) = 5 thru 12
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US Half Dollar
Width = 30.61 mm (1.205 In.)
Thickness (edge) = 2.15mm
Weight = 11.34g
Recommended ring size range (us) = 7 thru 13
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US Large Dollar
Width = 38.10 mm (1.5 In.)
Thickness (edge) = 2.58mm
Weight = 22.68g
Recommended ring size range (us) =13 thru 19
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American Silver Eagle- Dollar
Width = 40.6 mm (1.5 In.)
Thickness (edge) = 2.98mm.
Weight = 31.10g
Recommended ring size range (us) =13 thru 21