Round Australian Opal Ring

Circumference mm

Australia / NZ / UK

US / Canada

44.14

F

3

44.45

F 1/2

3 1/8

44.77

F 3/4

3 1/4

45.11

G

3 3/8

45.40

G 1/4

3 1/2

45.74

G 1/2

3 5/8

46.02

H

3 3/4

46.68

H 1/2

4

47.25

I

4 1/4

47.97

I 1/2

4 1/2

48.38

J

4 5/8

48.79

J 1/4

4 3/4

49.32

J 1/2

5

49.64

K

5 1/8

49.95

K 1/4

5 1/4

50.27

K 1/2

5 3/8

50.58

L

5 1/2

51.21

L 1/4

5 3/4

51.55

L 1/2

5 7/8

51.87

M

6

52.50

M 1/2

6 1/4

53.16

N

6 1/2

53.82

N 1/2

6 3/4

54.51

O

7

54.82

O 1/2

7 1/4

55.76

P

7 1/2

56.45

P 1/2

7 3/4

57.15

Q

8

57.65

Q 1/2

8 1/4

58.21

Q 3/4

8 1/2

58.47

R

8 5/8

58.72

R 1/4

8 3/4

59.06

R 1/2

8 7/8

59.34

R 3/4

9

60.00

S

9 1/8

60.38

S 1/4

9 1/4

60.66

S 1/2

9 3/8

60.98

S 3/4

9 1/2

61.29

T

9 5/8

61.64

T 1/4

9 3/4

62.33

T 1/2

10

62.89

U

10 1/4

63.46

U 1/2

10 1/2

63.84

V

10 5/8

64.21

V 1/4

10 3/4

64.97

V 1/2

11

65.22

W

11 1/8

65.50

W 1/4

11 1/4

65.78

W 1/2

11 3/8

66.22

W 3/4

11 1/2

66.54

X

11 5/8

66.73

X 1/4

11 3/4

66.92

X 1/2

11 7/8

67.51

Y

12

68.14

Y 1/2

12 1/4

68.77

Z

12 1/2

69.43

Z +1/2

12 3/4

70.15

Z+1

13