EU Ring Size Conversion Calculator & Chart – 2025 (EU, US, UK)

Precision EU Ring Size Conversion Calculator (International ring sizes)

If you know your ring size in a different format, you can use our other dedicated conversion tools. We have calculators based on the UK (Letter), US (Numerical), Japanese, and Swiss standards.

Once you have found your perfect size, we invite you to view our list of handmade silver filigree rings and silver opal rings.

Rounded EU Ring Size Conversion Calculator (0.5 mm increments)

EU Ring Size Precision Conversion Chart

EU (Inner Circumference in mm)	US & Canada	UK & Australia	Japan, China & S. America	Switzerland
37.5	0.5	A	0.5*	<0*
38.2	0.75	A ½	0.8*	<0*
38.9	1	B	1	<0*
39.5	1.25	B ½	1.5*	<0*
40.2	1.5	C	2	0.2
40.8	1.75	C ½	2.5*	0.8
41.5	2	D	3	1.5
42.1	2.25	D ½	3.5*	2.1
42.8	2.5	E	4	2.8
43.4	2.75	E ½	4.5*	3.4
44.1	3	F	5	4.1
44.7	3.25	F ½	5.5*	4.7
45.4	3.5	G	6	5.4
46.0	3.75	G ½	7	6.0
46.7	4	H	8	6.7
47.3	4.25	H ½	8.5*	7.3
48.0	4.5	I	9	8.0
48.6	4.75	I ½	9.5*	8.6
49.2	5	J	10	9.2
49.9	5.25	J ½	10.5*	9.9
50.5	5.5	K	11	10.5
51.2	5.75	K ½	11.5*	11.2
51.8	6	L	12	11.8
52.5	6.25	L ½	12.5*	12.5
53.1	6.5	M	13	13.1
53.8	6.75	M ½	13.5*	13.8
54.4	7	N	14	14.4
55.1	7.25	N ½	14.5*	15.1
55.7	7.5	O	15	15.7
56.4	7.75	O ½	15.5*	16.4
57.0	8	P	16	17.0
57.6	8.25	P ½	16.5*	17.6
58.3	8.5	Q	17	18.3
58.9	8.75	Q ½	17.5*	18.9
59.6	9	R	18	19.6
60.2	9.25	R ½	18.5*	20.2
60.9	9.5	S	19	20.9
61.5	9.75	S ½	19.5*	21.5
62.2	10	T	20	22.2
62.8	10.25	T ½	21	22.8
63.5	10.5	U	22	23.5
64.1	10.75	U ½	22.5*	24.1
64.7	11	V	23	24.7
65.4	11.25	V ½	23.5*	25.4
66.0	11.5	W	24	26.0
66.7	11.75	W ½	24.5*	26.7
67.3	12	X	25	27.3
68.0	12.25	X ½	25.5*	28.0
68.6	12.5	Y	26	28.6
69.2	12.75	Y ½	26.5*	29.2
69.9	13	Z	27	29.9
70.5	13.25	Z ½	27.5*	30.5
71.2	13.5	Z+1	28	31.2
72.5	14	Z+2	29*	32.5
73.7	14.5	Z+3	30*	33.7
74.8	15	Z+4	31*	34.8
76.0	15.5	Z+5	32*	36.0
76.9	16	Z+6	33*	36.9

Disclaimer: Values marked with an asterisk () are approximated as a direct, standardized equivalent is not available. Values marked as <0* are for sizes that are smaller than the official starting point of the Swiss sizing system and are mathematical extrapolations.*

EU Ring Size Rounded Conversion Chart

This user-friendly table has been recalculated to show EU sizes in clean 0.5 mm increments. All other values are interpolated to match.

EU (Inner Circumference in mm)	US & Canada	UK & Australia	Japan, China & S. America	Switzerland
40.0*	1.4*	C*	1.8*	0.0*
40.5*	1.6*	C*	2.2*	0.5*
41.0*	1.8*	C ½*	2.7*	1.0*
41.5*	2.0*	D*	3.0*	1.5*
42.0*	2.2*	D ½*	3.4*	2.0*
42.5*	2.4*	E*	3.8*	2.5*
43.0*	2.6*	E*	4.2*	3.0*
43.5*	2.8*	E ½*	4.6*	3.5*
44.0*	3.0*	F*	5.0*	4.0*
44.5*	3.2*	F ½*	5.4*	4.5*
45.0*	3.4*	G*	5.8*	5.0*
45.5*	3.6*	G*	6.2*	5.5*
46.0*	3.8*	G ½*	7.0*	6.0*
46.5*	4.0*	H*	7.7*	6.5*
47.0*	4.2*	H ½*	8.3*	7.0*
47.5*	4.4*	I*	8.8*	7.5*
48.0*	4.5*	I*	9.0*	8.0*
48.5*	4.7*	I ½*	9.5*	8.5*
49.0*	4.9*	J*	9.8*	9.0*
49.5*	5.1*	J*	10.2*	9.5*
50.0*	5.3*	K*	10.7*	10.0*
50.5*	5.5*	K*	11.0*	10.5*
51.0*	5.7*	K ½*	11.4*	11.0*
51.5*	5.9*	L*	11.8*	11.5*
52.0*	6.1*	L*	12.2*	12.0*
52.5*	6.3*	L ½*	12.5*	12.5*
53.0*	6.5*	M*	13.0*	13.0*
53.5*	6.7*	M ½*	13.4*	13.5*
54.0*	6.9*	N*	13.8*	14.0*
54.5*	7.1*	N*	14.2*	14.5*
55.0*	7.4*	N ½*	14.8*	15.0*
55.5*	7.6*	O*	15.2*	15.5*
56.0*	7.8*	O ½*	15.6*	16.0*
56.5*	8.1*	P*	16.2*	16.5*
57.0*	8.3*	P ½*	16.6*	17.0*
57.5*	8.5*	Q*	17.0*	17.5*
58.0*	8.6*	Q*	17.4*	18.0*
58.5*	8.8*	Q ½*	17.8*	18.5*
59.0*	9.0*	R*	18.0*	19.0*
59.5*	9.1*	R*	18.4*	19.5*
60.0*	9.3*	R ½*	18.8*	20.0*
60.5*	9.6*	S*	19.2*	20.5*
61.0*	9.8*	S ½*	19.6*	21.0*
61.5*	10.0*	T*	20.0*	21.5*
62.0*	10.1*	T*	20.4*	22.0*
62.5*	10.3*	T ½*	20.8*	22.5*
63.0*	10.5*	U*	21.5*	23.0*
63.5*	10.6*	U*	22.0*	23.5*
64.0*	10.8*	U ½*	22.4*	24.0*
64.5*	11.0*	V*	22.8*	24.5*
65.0*	11.2*	V ½*	23.2*	25.0*
65.5*	11.4*	W*	23.6*	25.5*
66.0*	11.5*	W*	24.0*	26.0*
66.5*	11.7*	W ½*	24.4*	26.5*
67.0*	11.9*	X*	24.8*	27.0*
67.5*	12.1*	X*	25.2*	27.5*
68.0*	12.3*	X ½*	25.5*	28.0*
68.5*	12.5*	Y*	26.0*	28.5*
69.0*	12.6*	Y ½*	26.4*	29.0*
69.5*	12.8*	Z*	26.8*	29.5*
70.0*	13.0*	Z*	27.2*	30.0*
70.5*	13.3*	Z ½*	27.5*	30.5*
71.0*	13.5*	Z+1*	27.8*	31.0*
71.5*	13.6*	Z+1*	28.2*	31.5*
72.0*	13.8*	Z+2*	28.6*	32.0*
72.5*	14.0*	Z+2*	29.0*	32.5*
73.0*	14.2*	Z+3*	29.5*	33.0*
73.5*	14.4*	Z+3*	30.0*	33.5*
74.0*	14.6*	Z+4*	30.5*	34.0*
74.5*	14.8*	Z+4*	31.0*	34.5*
75.0*	15.0*	Z+4*	31.5*	35.0*
75.5*	15.3*	Z+5*	31.8*	35.5*
76.0*	15.5*	Z+5*	32.0*	36.0*
76.5*	15.8*	Z+6*	32.5*	36.5*
77.0*	16.0*	Z+6*	33.0*	37.0*

Disclaimer: All values are mathematically interpolated for granularity and marked with an asterisk () to indicate they are high-quality approximations.*