RING SIZE CONVERSION CHART

INTERNAL DIAMETER.                         MM

   US & CANADA

BRITISH & AUSTRALIA

RUSSIA & FRANCE

GERMANY

JAPAN

SWISS

9.91

0

-

-

-

-

-

10.72

0

-

-

-

-

-

11.53

0

-

-

-

-

-

11.95

1/2

A

-

-

-

-

12.18

3/4

A 1/2

-

-

-

-

12.37

1

B

-

-

1

-

12.60

1 1/4

B 1/2

-

-

-

-

12.78

1 1/2

C

-

-

-

-

13.00

1 3/4

C 1/2

-

-

-

-

13.21

2

D

41 1/2

13 1/2

2

1 1/2

13.41

2 1/4

D 1/2

-

-

-

-

13.61

2 1/2

E

42 3/4

13 3/4

3

2 3/4

13.83

2 3/4

E 1/2

-

-

-

-

14.05

3

F

44

14

4

4

14.15

3 1/8

F 1/2

-

-

-

-

14.25

3 1/4

F 3/4

-

-

-

-

14.36

3 3/8

G

45 1/4

-

5

5 1/4

14.45

3 1/2

G 1/4

-

14 1/2

-

-

14.56

3 5/8

G 1/2

-

-

6

-

14.65

3 3/4

H

46 1/2

-

-

6 1/2

14.86

4

H 1/2

-

15

7

-

15.04

4 1/4

I

47 3/4

-

-

7 3/4

15.27

4 1/2

I 1/2

-

15 1/4

8

-

15.40

4 5/8

J

49

15 1/2

-

9

15.53

4 3/4

J 1/4

-

-

-

-

15.70

5

J 1/2

-

15 3/4

9

-

15.80

5 1/8

K

50

-

-

10

15.90

5 1/4

K 1/4

-

-

-

-

16.00

5 3/8

K 1/2

-

-

10

-

16.10

5 1/2

L

51 3/4

16

-

11 3/4

16.30

5 3/4

L 1/4

-

-

-

-

16.41

5 7/8

L 1/2

-

-

-

-

16.51

6

M

52 3/4

16 1/2

12

12 3/4

16.71

6 1/4

M 1/2

-

-

-

-

16.92

6 1/2

N

54

17

13

14

17.13

6 3/4

N 1/2

-

-

-

-

17.35

7

O

55 1/4

17 1/4

14

15 1/4

17.45

7 1/4

O 1/2

-

-

-

-

17.75

7 1/2

P

56 1/2

17 3/4

15

16 1/2

17.97

7 3/4

P 1/2

-

-

-

-

18.19

8

Q

57 3/4

18

16

17 3/4

18.35

8 1/4

Q 1/2

-

-

-

-

18.53

8 1/2

Q 3/4

-

18 1/2

17

-

18.61

8 5/8

R

59

-

-

19

18.69

8 3/4

R 1/4

-

-

-

-

18.80

8 7/8

R 1/2

-

-

-

-

18.89

9

R 3/4

-

19

18

-

19.10

9 1/8

S

60 1/4

-

-

20 1/4

19.22

9 1/4

S 1/4

-

-

-

-

19.31

9 3/8

S 1/2

-

-

-

-

19.41

9 1/2

S 3/4

-

19 1/2

19

-

19.51

9 5/8

T

61 1/2

-

-

21 1/2

19.62

9 3/4

T 1/4

-

-

-

-

19.84

10

T 1/2

-

20

20

-

20.02

10 1/4

U

62 3/4

-

21

22 3/4

20.20

10 1/2

U 1/2

-

20 1/4

22

-

20.32

10 5/8

V

63

-

-

23 3/4

20.44

10 3/4

V 1/4

-

-

-

-

20.68

11

V 1/2

-

20 3/4

23

-

20.76

11 1/8

W

65

-

-

25

20.85

11 1/4

W 1/4

-

-

-

-

20.94

11 3/8

W 1/2

-

-

-

-

21.08

11 1/2

W 3/4

-

21

24

-

21.18

11 5/8

X

66 1/4

-

-

26 1/4

21.24

11 3/4

X 1/4

-

-

-

-

21.30

11 7/8

X 1/2

-

-

-

-

21.49

12

Y

67 1/2

21 1/4

25

27 1/2

21.69

12 1/4

Y 1/2

-

-

-

-

21.89

12 1/2

Z

68 3/4

21 3/4

26

28 3/4

22.10

12 3/4

Z +1/2

-

-

-

-

22.33

13

Z+1

-

22

27

-

22.60

13.5

Z+1.5

-

-

-

-

22.69

-

Z+2

-

-

-

-

22.92

-

Z+2.5

-

-

-

-

23.06

-

Z+3

-

-

-

-

23.24

-

Z+3.5

-

-

-

-

23.47

-

Z+4

-

-

-

-

23.55

-

Z+4.5

-

-

-

-

23.87

-

Z+5

-

-

-

-

24.27

-

Z+6

-

-

-

-