Ring Size Equivalence Table
Ring Size Equivalence Table

Conversion Chart for Ring size

Inner

Inner

United States

United Kingdom

Japan

Italy

Diameter

Diameter

Canada

Ireland

China

Spain

 

 

 

Australia

India

Netherlands

(inch)

(mm)

 

New Zealand

Asia

Switzerland

0.554

14.07

3

F

4

4.25

0.562

14.27

3-1/4

F-1/2

5

4.75

0.570

14.48

3-1/2

G

 

5.5

0.578

14.68

3-3/4

G-1/2

6

6

0.586

14.88

4

H

7

6.75

0.594

15.09

4-1/4

H-1/2

 

7.5

0.602

15.29

4-1/2

I

8

8

0.610

15.49

4-3/4

J

 

8.75

0.618

15.70

5

J-1/2

9

9.25

0.626

15.90

5-1/4

K

 

10

0.634

16.10

5-1/2

K-1/2

10

10.5

0.642

16.31

5-3/4

L

 

1125

0.650

16.51

6

L-1/2

11

11.75

0.658

16.71

   6-1/4

M

12

12.5

0.666

16.92

6-1/2

M-1/2

13

13.25

0.674

17.12

6-3/4

N

 

13.75

0.682

17.32

7

N-1/2

14

14.5

0.690

17.53

7-1/4

O

 

15

0.698

17.73

7-1/2

O-1/2

15

15.75

0.706

17.93

7-3/4

P

 

16.25

0.714

18.14

8

P-1/2

16

17

0.722

18.34

8-1/4

Q

 

17.5

0.730

18.54

8-1/2

Q-1/2

17

18.25

0.738

18.75

8-3/4

R

 

19

Inner

Inner

United States

United Kingdom

Japan

Italy

Diameter

Diameter

Canada

Ireland

China

Spain

 

 

 

Australia

India

Netherlands

(inch)

(mm)

 

New Zealand

Asia

Switzerland

0.746

18.95

9

R-1/2

18

19.5

0.754

19.15

9-1/4

S

 

20.25

0.762

19.35

9-1/2

S-1/2

19

20.75

0.770

19.56

9-3/4

T

 

21.5

0.778

19.76

10

T-1/2

20

22

0.786

19.96

10-1/4

U

21

22.75

0.794

20.17

10-1/2

U-1/2

22

23.25

0.802

20.37

10-3/4

V

 

24

0.810

20.57

11

V-1/2

23

24.75

0.818

20.78

11-1/4

W

 

2525

0.826

20.98

11-1/2

W-1/2

24

26

0.834

21.18

11-3/4

X

 

26.5

0.842

21.39

12

X-1/2

25

27.25

0.850

21.59

   12-1/4 

Y

 

27.75

0.858

21.79

12-1/2

Z

26

28.5

0.866

22.00

12-3/4

Z-1/2

 

29

0.874

22.20

13

 

27

29.75

0.882

22.40

13-1/4

Z1

 

30.5

0.890

22.61

13-1/2

 

 

31

0.898

22.81

13-3/4

Z2

 

31.75

0.906

23.01

14

Z3

 

32.25

0.914

23.22

14-1/4

 

 

33

0.922

23.42

14-1/2

Z4

 

33.50

0.930

23.62

14-3/4

 

 

34.25

0.938

23.83

15

 

 

34.75

 

 

 

 

 

 

Finger sizing

Ring size is not the same as finger size. A professional jeweler can determine proper ring size using a set of steel gauge-rings. These "ring sizers" come in narrow and wide widths. Thin width ring sizers are for either men or women who plan to choose a narrower ring 7 millimeters or thinner. Wider ring sizers are best for either men or women who are selecting a ring with a shank 8 millimeters or wider. Fingers change over the course of the day due to diet or work affecting the results of gauge rings.

Other methods, such as measuring the finger with a strip of paper, or slipping the finger through pre-cut "measuring holes," are inaccurate. It has been recommended that fingers be measured at the end of the day, when they are at their largest diameters. Existing fitted rings can also be measured for increased accuracy. Other factors that can affect ring size include: the menstrual cycle, temperature, humidity, water retention, and exercise.

The best strategy for measurement is to purchase calipers that measure inside diameters. A tightly-calipered measurement should then be taken of various rings that fit; these should be noted and the corresponding size recorded. The mandrel, the tapered ring-measuring rod, should be regarded as only half-accurate. Different jewelers will employ the mandrel in different ways. For instance, one jeweler may use the mandrel and take an edge-of-the-ring reading; others will take the measure that corresponds to the largest finger the ring can fit. There is not a separate mandrel for men or women ring measurements.

It is best for the consumer to know and be firm about finger dimensions, because every jeweler or ring seller will think his or her method is the "best" ring-measuring method. It has often been suggested that the industry universally standardize on using inner diameter (the diameter of the finger) as the only size-number method of determination.

A wider band can be worn more loosely. Large knuckles/hands should wear a slightly loose ring, while slimmer knuckles/smaller hands will require a tighter ring. Some rings can be re-sized, but many cannot. Rings made of titanium or tungsten steel, stone-set rings with complicated or precise mountings, and extremely thin or wide rings cannot be re-sized.

A good way for a "rough-and-ready" measurement is to find a ring that is just smaller than the second knuckle of the finger. This way the fit is comfortable but will not slide off the finger. The method of trying on a ring and shaking the hand violently, to see if the ring comes off, is inadvisable and not very accurate.

Furthermore, every ring size chart will vary slightly in its standards. This always occurs unless one company has copied another company's size chart. Even the ISO, ringsmiths, and jewelers use different sizing standards, assigning different numbers to the same measurements. On one chart a diameter of 20.65mm may equal a size 10-3/4; on another chart, a similar number, such as 20.62mm, may read out as size 10. It is wise to keep all of the above firmly in mind when ring shopping.

If ordering from catalog or internet, always demand that the seller provide the inner diameter of a ring.

Online Ring Sizer

There are many ways to determine ring size online. Some have a ring-sizing chart to print out; others match a ring to a certain size on the user's display.. . Other methods require the user to print a sizer and measure his own finger, but this method does not guarantee good results at all. The user, by applying more tension alone, can get two or three sizes' difference, or more.