Conversion of overseas sizes to Japanese sizes. Tips on how to measure without making mistakes.

2026-05-08

Ring size descriptions vary from country to country. When considering foreign brands or imported jewelry, many people may be concerned that they do not know what size they are.

First, let's check the size comparisons for the major countries.

1. ring size comparison chart (JP / US / UK / EU)

Japan (JP)	United States (US)	United Kingdom (UK)	Europe (EU)
1	1	C	41
1.5	1.5	C+	41.5
2	2	D	42
2.5	2.25	D+	42.5
3	2.5	E	43
3.5	2.75	E+	43.5
4	3	F	44
4.5	3.25	F+	44.5
5	3.5	G	45
5.5	3.75	G+	45.5
6	4	G+	46
6.5	4.25	H	46.5
7	4.5	H+	47
7.5	4.6	I	47.5
8	4.7	I+	48
8.5	4.8	I++	48.5
9	5	J	49
9.5	5.25	J+	49.5
10	5.5	K	50
10.5	5.75	K+ (Japanese kick-boxing promotion)	50.5
11	6	L	51
11.5	6.25	L+	51.5
12	6.5	L++	52
12.5	6.6	M	52.5
13	6.7	M+	53
13.5	6.9	N	53.5
14	7	N+	54
14.5	7.25	O	54.5
15	7.5	O+	55
15.5	7.75	O++	55.5
16	8	p	56
16.5	8.25	P+ (e.g. P+++A+B+)	56.5
17	8.5	Q	57
17.5	8.75	Q+	57.5
18	9	R	58
18.5	9.25	R+	58.5
19	9.5	S	59
19.5	9.75	S+	59.5
20	10	T	60
20.5	10.1	T+.	60.5
21	10.2	T++	61
21.5	10.3	T+++	61.5
22	10.5	U	62
22.5	10.75	U+	62.5
23	11	V	63
23.5	10.25	V+	63.5
24	11.5	W	64
24.5	11.75	W+	64.5
25	12	X	65

*Please use this as a guide, as there may be slight variations depending on the brand and design.

2. the "point of measurement" to avoid failure

There is a method of measuring with string or paper on the net, but we do not recommend this method because it can cause large errors depending on the shape of the fingers and the force with which the measurement is taken.

The most reliable way is to take measurements using a "special ring gauge" at your local jewelry store.

リングサイズ計測 — We offer two types of widths: normal and wide.

In doing so, please keep the following points in mind.

(1) Match the design (width)

The wider the ring, the more ground contact area it has, and the easier it is to feel pressure.

Wide and thick (from 3mm): Sizes measured with a normal narrow gauge will feel tight. Ideally, the same width gauge should be used.
Slender and V-shaped (2 mm or less): Because it slips in easily, it may feel a little loose.

リング幅 — Narrow and thick widths have different pressure sensations

The left one is about 2mm wide and feels a little loose, but at about 4mm it feels a little small.

2) Consider "joint thickness" (especially common type in men)

For those who have a thin base of the finger but a thick second joint, the ring will not fit if it is sized to fit the base of the finger. If the ring just barely passes through the joint and rotates at the base, it is recommended to use a design (such as a ring with a pattern around the entire circumference).

3. changes in size due to "physical condition" and "season".

In fact, finger thickness is not constant.

Changes within a day: Some people change about 0.5 to 1 from morning to evening.
Seasonal/climatic changes: In summer, water intake and heat can cause swelling, and in winter, dryness and cold can cause thinner fingers. In addition, the size of the body also changes in humid and dry countries.

Even if you measure once and think, "Is it a little tight (or loose)?" the trick is to try several times in different seasons and at different times to find the truly best size.

4. our after-sales service and "resizing" concept

We offer the following services to ensure your peace of mind after your purchase.

✨Affordable after-sales support ✨ Free resizing within ±3 sizes!

However, there is one important thing we would like to tell you. Resizing is a process where the ring is cut once, fired and welded again. Although skilled craftsmen perform this process carefully, it is not easy on the metal.

In order to maintain the strength of the ring and ensure its longevity,Ideally, resizing should be done as infrequently as possible.It is.

Even if you feel "a little uncomfortable," try first to see how you feel throughout the year (experiencing all four seasons). If you still need to make adjustments, we are always here to help.