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

When buying jewelry, getting the right ring size is essential, but it becomes tricky when shopping internationally. The primary issue is the lack of a universal sizing standard. A common “Size 7” in the US is known as a “Size N” in the UK. In contrast, the Swiss sizing standard directly uses the ring’s internal circumference in millimeters, where a ring with a 54mm circumference is labeled as a size ’54’.

To solve this problem, we offer a free Swiss ring size conversion calculator on this page. It is designed to help you easily translate your Swiss ring size to its international equivalent. With this tool, you can confidently purchase the correctly sized ring from any online retailer worldwide, eliminating any sizing concerns.

Rounded Swiss Ring Size Conversion Calculator (0.5 increments)

To use the Swiss Ring Size Conversion Calculator, simply select your Swiss ring size from the dropdown bar below, and see the equivalent units for Europe, the US, and Asia, among other regions.

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)

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

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. These units were measured based on international standards according to this international ring size chart.

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.