Ring Size Conversion Chart - Equivalents

September 08, 2013

Shopping for a Celtic Ring but unsure of your size? Use the chart below to convert between US/Canadian number sizes and the "Wheat Sheaf" letter system used in Ireland, UK, and Australia. Diameters and circumferences are given in both inches and millimetres. If you don't know your size at all, check out our guide on finding her ring size without ruining the surprise—the paper trick works for finding your own size too!

Average Women's Sizes

US Size 6–8 (UK L–Q)
Most jewelers sample in size 7
Shop Women's Rings →

Average Men's Sizes

US Size 9–11 (UK R–W)
Most jewelers sample in size 10
Shop Men's Rings →

Note: Ring sizing gauges and published charts do not always agree. The information below is the result of careful study and comparison of various sources, consistent with the instruments and measuring technique we use in our workshop.

Ring Size Conversion Chart

Diameter (inches)	Diameter (mm)	Circumference (inches)	Circumference (mm)	US/Canada	UK/Ireland Australia	Japan	Swiss
0.458	11.6	1.438	36.5	0	—	—	—
0.474	12.0	1.488	37.8	½	A	—	—
0.490	12.4	1.539	39.1	1	B	1	—
0.506	12.9	1.589	40.4	1½	C	—	—
0.522	13.3	1.639	41.6	2	D	2	1.50
0.538	13.7	1.689	42.9	2½	E	3	2.75
0.554	14.1	1.740	44.2	3	F	4	4.00
0.570	14.5	1.790	45.5	3½	G	—	—
0.586	14.9	1.840	46.7	4	H	7	—
0.602	15.3	1.890	48.0	4½	I	8	—
0.618	15.7	1.941	49.3	5	J½	9	—
0.634	16.1	1.991	50.6	5½	K½	10	—
0.650	16.5	2.041	51.8	6	L½	11	12.75
0.666	16.9	2.091	53.1	6½	M½	13	14.00
0.682	17.3	2.141	54.4	7 ★	N½	14	15.25
0.698	17.7	2.192	55.7	7½	O½	15	16.50
0.714	18.1	2.242	56.9	8	P½	16	17.75
0.730	18.5	2.292	58.2	8½	Q½	17	—
0.746	18.9	2.342	59.5	9	R½	18	—
0.762	19.4	2.393	60.8	9½	S½	19	—
0.778	19.8	2.443	62.1	10 ★	T½	20	—
0.794	20.2	2.493	63.3	10½	U½	22	22.75
0.810	20.6	2.543	64.6	11	V½	23	—
0.826	21.0	2.594	65.9	11½	W½	24	—
0.842	21.4	2.644	67.2	12	X½	25	27.50
0.858	21.8	2.694	68.4	12½	Z	26	28.75
0.874	22.2	2.744	69.7	13	—	27	—
0.906	23.0	2.845	72.3	14	Z3	—	—
0.938	23.8	2.945	74.8	15	—	—	—
0.970	24.6	3.046	77.4	16	—	—	—

★ = Most common sample size (Size 7 for women, Size 10 for men)

Reality Check: Sizing Tips

Rings and gauges are hard metal objects that can be measured exactly, but your finger is flesh and bone. Your finger is not perfectly round and cannot be measured with the same degree of accuracy as the ring. At the end of the day, the right ring is one that will stay on comfortably.

📏 Factors That Affect Size

Temperature & humidity
Exercise & diet
Time of day
Time of month / pregnancy
Dominant hand is usually ½ size larger

✓ Best Fit Guidelines

Should fit snugly with slight resistance when removing
Wider rings should be slightly looser than narrow rings
Quarter sizes help achieve the best fit
Men: if new to rings, proper size will feel tight at first—don't go too loose!

How We Measure: True Diameter Method

At Walker Metalsmiths, we use the True Diameter Method. The mark is read at the point where the wider side of the taper meets the edge of the ring. Wide rings are occasionally tapered and the smaller edge should be taken as the true size since this is the diameter of the largest finger that can fit into it.

Some jewelers use the Center Line Method, where the mark at the center of the ring is judged to be the size. Using this method, a wider ring will be measured at a size slightly smaller than its true diameter due to the taper of the sizing gauge. Because a ring size is a definition of diameter, we believe it is proper that a ring actually measures the true diameter rather than contain a fudge factor for width. Your local jeweler may disagree—calibration of gauges from different manufacturers may also vary.

Ready to Find Your Perfect Ring?

All our rings are available in quarter sizes for the best fit. Custom sizing is always available.

All Celtic Rings Wedding Bands Engagement Rings

Helpful Ring Resources

How to Find Her Ring Size Without Ruining the Surprise
Sterling Silver Celtic Rings
Gold Celtic Rings
Claddagh Rings — Ireland's ring of love, loyalty, and friendship
Contact Us — Questions about sizing? We're here to help!

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