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

Finding your perfect ring size is the most critical step in buying jewelry, yet it can be surprisingly complex, especially in a global online marketplace. The challenge is that ring sizing isn’t universal. A ‘Size 7’ in the United States is a ‘Size N’ in the United Kingdom, and something else entirely in the European Union, where sizing is often based on the ring’s inner circumference in millimeters, like an EU Size 54.

On this page, you will find our free EU ring size conversion calculator to help you convert your EU ring size to all other international ring size regions. This will help you choose the correct ring size from any online jewelry store, without any worries.

Precision EU Ring Size Conversion Calculator (International ring sizes)

To use the EU Ring Size Conversion Calculator, simply select your EU 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), 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.

Rounded EU Ring Size Conversion Calculator (0.5 mm increments)

EU Ring Size Precision Conversion Table

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

EU Ring Size Rounded Conversion Table

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

EU (Inner Circumference in mm)	US & Canada	UK & Australia	Japan, China & S. America	Switzerland
40.0*	1.4*	C*	1.8*	0.0*
40.5*	1.6*	C*	2.2*	0.5*
41.0*	1.8*	C ½*	2.7*	1.0*
41.5*	2.0*	D*	3.0*	1.5*
42.0*	2.2*	D ½*	3.4*	2.0*
42.5*	2.4*	E*	3.8*	2.5*
43.0*	2.6*	E*	4.2*	3.0*
43.5*	2.8*	E ½*	4.6*	3.5*
44.0*	3.0*	F*	5.0*	4.0*
44.5*	3.2*	F ½*	5.4*	4.5*
45.0*	3.4*	G*	5.8*	5.0*
45.5*	3.6*	G*	6.2*	5.5*
46.0*	3.8*	G ½*	7.0*	6.0*
46.5*	4.0*	H*	7.7*	6.5*
47.0*	4.2*	H ½*	8.3*	7.0*
47.5*	4.4*	I*	8.8*	7.5*
48.0*	4.5*	I*	9.0*	8.0*
48.5*	4.7*	I ½*	9.5*	8.5*
49.0*	4.9*	J*	9.8*	9.0*
49.5*	5.1*	J*	10.2*	9.5*
50.0*	5.3*	K*	10.7*	10.0*
50.5*	5.5*	K*	11.0*	10.5*
51.0*	5.7*	K ½*	11.4*	11.0*
51.5*	5.9*	L*	11.8*	11.5*
52.0*	6.1*	L*	12.2*	12.0*
52.5*	6.3*	L ½*	12.5*	12.5*
53.0*	6.5*	M*	13.0*	13.0*
53.5*	6.7*	M ½*	13.4*	13.5*
54.0*	6.9*	N*	13.8*	14.0*
54.5*	7.1*	N*	14.2*	14.5*
55.0*	7.4*	N ½*	14.8*	15.0*
55.5*	7.6*	O*	15.2*	15.5*
56.0*	7.8*	O ½*	15.6*	16.0*
56.5*	8.1*	P*	16.2*	16.5*
57.0*	8.3*	P ½*	16.6*	17.0*
57.5*	8.5*	Q*	17.0*	17.5*
58.0*	8.6*	Q*	17.4*	18.0*
58.5*	8.8*	Q ½*	17.8*	18.5*
59.0*	9.0*	R*	18.0*	19.0*
59.5*	9.1*	R*	18.4*	19.5*
60.0*	9.3*	R ½*	18.8*	20.0*
60.5*	9.6*	S*	19.2*	20.5*
61.0*	9.8*	S ½*	19.6*	21.0*
61.5*	10.0*	T*	20.0*	21.5*
62.0*	10.1*	T*	20.4*	22.0*
62.5*	10.3*	T ½*	20.8*	22.5*
63.0*	10.5*	U*	21.5*	23.0*
63.5*	10.6*	U*	22.0*	23.5*
64.0*	10.8*	U ½*	22.4*	24.0*
64.5*	11.0*	V*	22.8*	24.5*
65.0*	11.2*	V ½*	23.2*	25.0*
65.5*	11.4*	W*	23.6*	25.5*
66.0*	11.5*	W*	24.0*	26.0*
66.5*	11.7*	W ½*	24.4*	26.5*
67.0*	11.9*	X*	24.8*	27.0*
67.5*	12.1*	X*	25.2*	27.5*
68.0*	12.3*	X ½*	25.5*	28.0*
68.5*	12.5*	Y*	26.0*	28.5*
69.0*	12.6*	Y ½*	26.4*	29.0*
69.5*	12.8*	Z*	26.8*	29.5*
70.0*	13.0*	Z*	27.2*	30.0*
70.5*	13.3*	Z ½*	27.5*	30.5*
71.0*	13.5*	Z+1*	27.8*	31.0*
71.5*	13.6*	Z+1*	28.2*	31.5*
72.0*	13.8*	Z+2*	28.6*	32.0*
72.5*	14.0*	Z+2*	29.0*	32.5*
73.0*	14.2*	Z+3*	29.5*	33.0*
73.5*	14.4*	Z+3*	30.0*	33.5*
74.0*	14.6*	Z+4*	30.5*	34.0*
74.5*	14.8*	Z+4*	31.0*	34.5*
75.0*	15.0*	Z+4*	31.5*	35.0*
75.5*	15.3*	Z+5*	31.8*	35.5*
76.0*	15.5*	Z+5*	32.0*	36.0*
76.5*	15.8*	Z+6*	32.5*	36.5*
77.0*	16.0*	Z+6*	33.0*	37.0*

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

Beyond the Ruler: Key Factors That Influence Your Ring Size

So you’ve measured your finger with the ring size chart, and have your number. Excellent start, but the job isn’t quite finished. Your ring size isn’t a single, static measurement; it’s a dynamic variable that can change throughout the day.

Furthermore, the ring’s own design, particularly its width, plays a massive role in how it actually feels on your hand. Understanding these nuances is the secret to moving from a “good enough” fit to a truly perfect one, ensuring your ring is always comfortable and secure.

• Your Body’s Natural Rhythms: Your fingers are constantly changing. They can swell in the heat or after a salty meal and shrink in the cold. To find a reliable average, it’s best to measure your finger 3-4 times throughout the day when your body is at a neutral, room temperature state. This will help you find a size that’s comfortable most of the time.
• The Width of the Band: This is a critical and often overlooked detail. A wide band (typically 6mm or more) covers more skin and creates a snugger fit than a delicate, thin band of the same size. As a non-negotiable rule of thumb, you should always go up a quarter to a half size for wider rings to ensure they slide on comfortably.
• The Knuckle Challenge: For some, the main obstacle is the knuckle. If your knuckle is noticeably larger than the base of your finger, you need to find a size that can comfortably clear that hurdle without being so loose that it spins uncontrollably once it’s on. This often means finding a happy medium between the two measurements.

By accounting for these crucial variables, from your body’s daily fluctuations to the ring’s physical dimensions, you are moving beyond a simple number to a truly accurate understanding of your size. This knowledge is the key to confidently choosing a ring that will feel secure, comfortable, and ideally suited to your hand for years to come.