Sizing Tips

Ring Size Chart for ISO/EU Rings

Our size chart is ideal for anyone purchasing a ring in EU/ISO millimeter-based sizes, as it provides the converted sizes in all major international systems. With our chart, you can easily find the corresponding US, IT, UK, East Asian and circumference measurements for each EU/ISO ring size:

ISO / EU	Circum.	Diam.	US	UK	IT	East Asia
40	40.0mm (1.57")	12.7mm	1 ¼	C	0	1
41	41.0mm (1.61")	13.1mm	1 ¾	D	1	1
42	42.0mm (1.65")	13.4mm	2 ¼	D 1/2	2	2
43	43.0mm (1.69")	13.7mm	2 ½	E 1/2	3	3
44	44.0mm (1.73")	14.0mm	3	F	4	4
45	45.0mm (1.77")	14.3mm	3 ¼	G	5	5
46	46.0mm (1.81")	14.6mm	3 ¾	H	6	6
47	47.0mm (1.85")	15.0mm	4	H 1/2	7	7
48	48.0mm (1.89")	15.3mm	4 ½	I 1/2	8	8
49	49.0mm (1.93")	15.6mm	5	J	9	9
50	50.0mm (1.97")	15.9mm	5 ¼	K	10	10
51	51.0mm (2.01")	16.2mm	5 ¾	L	11	11
52	52.0mm (2.05")	16.6mm	6	L 1/2	12	12
53	53.0mm (2.09")	16.9mm	6 ½	M 1/2	13	13
54	54.0mm (2.13")	17.2mm	6 ¾	N	14	14
55	55.0mm (2.17")	17.5mm	7 ¼	O	15	15
56	56.0mm (2.20")	17.8mm	7 ¾	P	16	15
57	57.0mm (2.24")	18.1mm	8	P 1/2	17	16
58	58.0mm (2.28")	18.5mm	8 ½	Q 1/2	18	17
59	59.0mm (2.32")	18.8mm	8 ¾	R	19	18
60	60.0mm (2.36")	19.1mm	9 ¼	S	20	19
61	61.0mm (2.40")	19.4mm	9 ½	T	21	20
62	62.0mm (2.44")	19.7mm	10	T 1/2	22	21
63	63.0mm (2.48")	20.1mm	10 ½	U 1/2	23	22
64	64.0mm (2.52")	20.4mm	10 ¾	V	24	23
65	65.0mm (2.56")	20.7mm	11 ¼	W	25	24
66	66.0mm (2.60")	21.0mm	11 ½	X	26	25
67	67.0mm (2.64")	21.3mm	12	X 1/2	27	26
68	68.0mm (2.68")	21.6mm	12 ¼	Y 1/2	28	27
69	69.0mm (2.72")	22.0mm	12 ¾	Z	29	28
70	70.0mm (2.76")	22.3mm	13 ¼	Z1	30	29
71	71.0mm (2.80")	22.6mm	13 ½	Z2	31	30
72	72.0mm (2.83")	22.9mm	14	Z2 1/2	32	31
73	73.0mm (2.87")	23.2mm	14 ¼	Z3 1/2	33	32
74	74.0mm (2.91")	23.6mm	14 ¾	Z4	34	33
75	75.0mm (2.95")	23.9mm	15	Z4	35	34

Understanding International Ring Sizes: A Guide Centered on EU/ISO Standards

When purchasing rings internationally, the EU/ISO sizing system serves as the most logical and precise foundation for understanding ring measurements across different markets. This millimeter-based approach provides clarity and accuracy that makes converting between various national systems straightforward.

EU/ISO Ring Sizing: The Universal Standard

The European (EU) ring sizing system, officially recognized as ISO standard, measures the internal circumference of a ring in millimeters. This direct measurement approach eliminates guesswork—an EU size 52 indicates a ring with exactly 52mm internal circumference. This precision makes EU sizing the most reliable reference point for international ring shopping.

The EU system typically ranges from size 40mm (very small) to 76mm (very large), with standard increments that accommodate virtually all finger sizes. This millimeter-based measurement translates directly to circumference, creating a seamless understanding of actual ring dimensions.

Converting EU/ISO Sizes to Other International Systems

US and North American Sizing

The United States, Canada, and Mexico employ a numbered system where EU sizes convert predictably. A popular EU size 54 translates to approximately US size 7, while EU 52 corresponds to US size 6. US sizing increases in quarter-size increments (6, 6.25, 6.5, 6.75, 7), spanning roughly from US size 3 (EU 44) to US size 13 (EU 70).

UK and Commonwealth Sizing

British sizing uses letters from A through Z and beyond. The conversion from EU sizing follows a clear pattern: EU size 54 equals UK size N, EU size 52 matches UK size L. This alphabetical system serves the United Kingdom, Ireland, Australia, South Africa, and New Zealand.

Italian and Mediterranean Sizing

Italian sizing, used across Italy, Spain, Netherlands, and Switzerland, typically subtracts 40 from the EU measurement. Therefore, EU size 54 becomes Italian size 14, and EU size 52 converts to Italian size 12. This consistent offset makes conversion calculations simple.

Asian Diameter-Based Systems

East and Southeast Asian countries, including Japan, China, South Korea, and parts of South America, use a diameter-based system rather than circumference. Their sizing begins at size 1 (13mm internal diameter) and increases by 0.33mm increments. To convert from EU circumference to Asian sizing, divide the EU size by π (3.14159) to get diameter, then apply the Asian size formula.

Why EU/ISO Sizing Provides the Best Reference Point

Using EU/ISO sizing as your primary reference offers several advantages:

Precision: Millimeter measurements eliminate ambiguity
Universal Understanding: Most international jewelers recognize EU sizing
Easy Conversion: Other systems convert predictably from EU measurements
Scientific Accuracy: Based on actual physical dimensions rather than arbitrary numbering

For optimal results when shopping internationally, measure your finger circumference in millimeters first, then identify your EU size. This measurement serves as your reliable foundation for converting to any regional sizing system, ensuring perfect fit regardless of where you purchase your ring.