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

UK Ring Size Conversion Calculator

If you know your ring size in a different format, you can use our other dedicated conversion tools. We have calculators based on the US (Numerical), EU (Circumference), 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.

UK Ring Size Conversion Chart

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