Home / UK to US ring sizes

UK to US ring size conversion

UK, Irish and Australian ring sizes are letters; US sizes are numbers. Each UK letter adds 1.25 mm around, and each US size adds about 2.55 mm, so a US size spans roughly two letters.

UK / AU size

US / Canada: 7
UK / Australia: N½
EU / ISO: 54
Japan / China: 14
India: 14
Italy / Spain / CH: 14
Inside diameter: 17.3 mm
Circumference: 54.4 mm
Diameter (in): 0.681″

UK to US ring size table

UK / AU / NZ	US (nearest ¼)	US exact	EU	Circumference	Diameter
F	2¾	2.82	44	43.75 mm	13.9 mm
F½	3	3.07	44	44.38 mm	14.1 mm
G	3¼	3.31	45	45.00 mm	14.3 mm
G½	3½	3.56	46	45.63 mm	14.5 mm
H	3¾	3.80	46	46.25 mm	14.7 mm
H½	4	4.05	47	46.88 mm	14.9 mm
I	4¼	4.29	48	47.50 mm	15.1 mm
I½	4½	4.54	48	48.13 mm	15.3 mm
J	4¾	4.78	49	48.75 mm	15.5 mm
J½	5	5.03	49	49.38 mm	15.7 mm
K	5¼	5.27	50	50.00 mm	15.9 mm
K½	5½	5.52	51	50.63 mm	16.1 mm
L	5¾	5.76	51	51.25 mm	16.3 mm
L½	6	6.01	52	51.88 mm	16.5 mm
M	6¼	6.25	53	52.50 mm	16.7 mm
M½	6½	6.50	53	53.13 mm	16.9 mm
N	6¾	6.74	54	53.75 mm	17.1 mm
N½	7	6.99	54	54.38 mm	17.3 mm
O	7¼	7.23	55	55.00 mm	17.5 mm
O½	7½	7.48	56	55.63 mm	17.7 mm
P	7¾	7.72	56	56.25 mm	17.9 mm
P½	8	7.96	57	56.88 mm	18.1 mm
Q	8¼	8.21	58	57.50 mm	18.3 mm
Q½	8½	8.45	58	58.13 mm	18.5 mm
R	8¾	8.70	59	58.75 mm	18.7 mm
R½	9	8.94	59	59.38 mm	18.9 mm
S	9¼	9.19	60	60.00 mm	19.1 mm
S½	9½	9.43	61	60.63 mm	19.3 mm
T	9¾	9.68	61	61.25 mm	19.5 mm
T½	10	9.92	62	61.88 mm	19.7 mm
U	10¼	10.17	63	62.50 mm	19.9 mm
U½	10½	10.41	63	63.13 mm	20.1 mm
V	10¾	10.66	64	63.75 mm	20.3 mm
V½	11	10.90	64	64.38 mm	20.5 mm
W	11¼	11.15	65	65.00 mm	20.7 mm
W½	11½	11.39	66	65.63 mm	20.9 mm
X	11¾	11.64	66	66.25 mm	21.1 mm
X½	12	11.88	67	66.88 mm	21.3 mm
Y	12¼	12.13	68	67.50 mm	21.5 mm
Y½	12¼	12.37	68	68.13 mm	21.7 mm
Z	12½	12.62	69	68.75 mm	21.9 mm
Z+1	13	13.10	70	70.00 mm	22.3 mm
Z+2	13½	13.59	71	71.25 mm	22.7 mm
Z+3	14	14.08	73	72.50 mm	23.1 mm
Z+4	14½	14.57	74	73.75 mm	23.5 mm
Z+5	15	15.06	75	75.00 mm	23.9 mm

US to UK: the quick rule of thumb

Around the middle of the range, US 6 ≈ L½, 7 ≈ N½, 8 ≈ P½, 9 ≈ R½, 10 ≈ T½. Each extra US size is two letters. The rule slowly drifts at the ends of the scale, so use the table or the converter for anything below US 4 or above US 11.

Questions people ask

What is a UK N in US ring size?

UK N is US 6¾ (54.2 mm inside circumference). UK N½ is the usual equivalent of a US 7.

What is UK L in US sizes?

UK L is US 5¾, and L½ is US 6.

Are Australian and New Zealand ring sizes the same as UK?

Yes. Australia, New Zealand, Ireland and South Africa use the same alphabetical BS 6820 scale as the UK.

What comes after UK size Z?

Sizes beyond Z are written Z+1, Z+2 and so on, each adding another 1.25 mm of circumference. Z+1 is about a US 13.