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

Rounded Swiss Ring Size Conversion Calculator (0.5 increments)

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), EU (Circumference), and Japanese standards.

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

Precision Swiss Ring Size Conversion Calculator (International ring sizes)

Rounded Swiss Ring Size Conversion Chart (0.5 increments)

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

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

Precision Swiss Ring Size Conversion Calculator (International ring sizes)

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

Disclaimer: Values marked with an asterisk () are approximated as a direct, standardized equivalent is not available.*