Ring sizing chart

Inside Diameter 

Inside Circumference

Sizes

MM

Inches

MM

Inches

UK / AUS

 US / CA

9.91

0.39

31.13

1.22

-

0

10.72

0.442

33.68

1.39

-

0

11.53

0.454

36.22

1.43

-

0

11.95

0.474

37.54

1.49

A

1/2

12.18

0.482

38.26

1.51

A 1/2

3/4

12.37

0.487

38.86

1.53

B

1

12.6

0.496

39.58

1.56

B 1/2

1 1/4

12.78

0.503

40.15

1.58

C

1 1/2

13

0.512

40.84

1.61

C 1/2

1 3/4

13.21

0.52

41.5

1.63

D

2

13.41

0.528

42.13

1.66

D 1/2

2 1/4

13.61

0.536

42.76

1.68

E

2 1/2

13.83

0.544

43.45

1.71

E 1/2

2 3/4

14.05

0.553

44.14

1.74

F

3

14.15

0.557

44.45

1.75

F 1/2

3 1/8

14.25

0.561

44.77

1.76

F 3/4

3 1/4

14.36

0.565

45.11

1.77

G

3 3/8

14.45

0.569

45.4

1.79

G 1/4

3 1/2

14.56

0.573

45.74

1.8

G 1/2

3 5/8

14.65

0.577

46.02

1.81

H

3 3/4

14.86

0.585

46.68

1.84

H 1/2

4

15.04

0.592

47.25

1.86

I

4 1/4

15.27

0.601

47.97

1.89

I 1/2

4 1/2

15.4

0.606

48.38

1.9

J

4 5/8

15.53

0.611

48.79

1.92

J 1/4

4 3/4

15.7

0.618

49.32

1.94

J 1/2

5

15.8

0.622

49.64

1.95

K

5 1/8

15.9

0.626

49.95

1.97

K 1/4

5 1/4

16

0.63

50.27

1.98

K 1/2

5 3/8

16.1

0.634

50.58

1.99

L

5 1/2

16.3

0.642

51.21

2.02

L 1/4

5 3/4

16.41

0.646

51.55

2.03

L 1/2

5 7/8

16.51

0.65

51.87

2.04

M

6

16.71

0.658

52.5

2.07

M 1/2

6 1/4

16.92

0.666

53.16

2.09

N

6 1/2

17.13

0.674

53.82

2.12

N 1/2

6 3/4

17.35

0.683

54.51

2.15

O

7

17.45

0.687

54.82

2.16

O 1/2

7 1/4

17.75

0.699

55.76

2.2

P

7 1/2

17.97

0.707

56.45

2.22

P 1/2

7 3/4

18.19

0.716

57.15

2.25

Q

8

18.35

0.722

57.65

2.27

Q 1/2

8 1/4

18.53

0.729

58.21

2.29

Q 3/4

8 1/2

18.61

0.733

58.47

2.3

R

8 5/8

18.69

0.736

58.72

2.31

R 1/4

8 3/4

18.8

0.74

59.06

2.32

R 1/2

8 7/8

18.89

0.748

59.34

2.35

R 3/4

9

19.1

0.752

60

2.36

S

9 1/8

19.22

0.757

60.38

2.38

S 1/4

9 1/4

19.31

0.76

60.66

2.39

S 1/2

9 3/8

19.41

0.764

60.98

2.4

S 3/4

9 1/2

19.51

0.768

61.29

2.41

T

9 5/8

19.62

0.772

61.64

2.43

T 1/4

9 3/4

19.84

0.781

62.33

2.45

T 1/2

10

20.02

0.788

62.89

2.48

U

10 1/4

20.2

0.797

63.46

2.5

U 1/2

10 1/2

20.32

0.8

63.84

2.51

V

10 5/8

20.44

0.805

64.21

2.53

V 1/4

10 3/4

20.68

0.814

64.97

2.56

V 1/2

11

20.76

0.817

65.22

2.57

W

11 1/8

20.85

0.821

65.5

2.58

W 1/4

11 1/4

20.94

0.824

65.78

2.59

W 1/2

11 3/8

21.08

0.83

66.22

2.61

W 3/4

11 1/2

21.18

0.834

66.54

2.62

X

11 5/8

21.24

0.836

66.73

2.63

X 1/4

11 3/4

21.3

0.839

66.92

2.64

X 1/2

11 7/8

21.49

0.846

67.51

2.66

Y

12

21.69

0.854

68.14

2.68

Y 1/2

12 1/4

21.89

0.862

68.77

2.71

Z

12 1/2

22.1

0.87

69.43

2.73

Z +1/2

12 3/4

22.33

0.879

70.15

2.76

Z+1

13

22.6

0.89

71

2.8

Z+1.5

13.5

22.69

0.893

71.28

2.81

Z+2

-

22.92

0.902

72

2.83

Z+2.5

-

23.06

0.908

72.45

2.85

Z+3

-

23.24

0.915

73.01

2.87

Z+3.5

-

23.47

0.924

73.73

2.9

Z+4

-

23.55

0.927

73.98

2.91

Z+4.5

-

23.87

0.94

74.99

2.95

Z+5

-

24.27

0.956

76.25

3

Z+6

-

What is the circumference of a ring?

The enclosed inner boundary and distance of the circle inside the ring.

What is the diameter of a ring?

The measurement of a straight line passing from side to side through the centre of the circle inside the ring.


It’s important to understand what ring sizing actually is. Ring size and finger size are two different things entirely. A ring is a solid, hard piece of material usually metal and it does not bend and squash to the shape of your finger. Your finger is never going to have this exact shape because it will increase in size and thin out over time, it will also swell and shrink with different temperatures etc.

If it is a wide band you should allow for a larger size. Somewhere between a half to a full size extra. The same goes with a fine band, you will need a really snug fit, closer to going down half a size.

It is a good idea to measure the finger at the end of the day, when the finger is at its largest, and not to do it when the finger is cold, as this will make it unusually small. 

Bear in mind that finger sizes change throughout the day.

You can use the above conversion chart to figure out your ring size very simply.

How to measure your finger size if you have a ring to compare.

Firstly measure the inside diameter of the ring. This is a measurement taken across the centre of the ring from the inside of one side to the inside of the other side. It is not easy and remember you are only concerned with the inside of the ring as that is where the finger goes. Make a couple of attempts and remember that the largest measurement is going to be the correct one. So once you have found that a couple of times you can be fairly sure that it is accurate. 

Next you can measure the inside circumference of the ring 

Get a stiff piece of paper as thin as possible and slide it inside the ring until it fits perfectly. Keep cutting little bits off the ends until both ends fit together snugly. You will then have an inside length that you can measure accurately. Allow a touch extra because the paper will have taken up a bit of space inside the ring. Then measure the length of the paper.  Now you have two measurements to compare with the chart. 

You only need one but using the two will give greater accuracy as one will be a check on the other.

Now that you have the length of the inside of the ring mark this length on a piece of very stiff paper or thin cardboard. Now tape it together so that it looks like a ring. Make it as wide as the real ring. Put this on your finger and then try the real ring on. Both of these have to be the same. Even if they do not fit your finger if it is not your ring, they will both fit on the exact same position on your finger.

Next check the inside diameter and inside circumference against the chart and read the size. 

Now you must be very close to the real size if you have been careful. 

How to measure you partner’s ring size in secret.

If you can get to a jeweller you can do this: Put your partner’s ring on your finger. Pick a finger where the ring fits as close to a normal position as possible. Mark two marks, one on either side of the ring. Leave them there and go to a jeweller and tell them you want to find out what size ring goes on your finger where these marks are. That is going to get very close to what you need. Make sure it goes past a knuckle as this is eventually going to happen with the real ring. 

How to measure your own finger size when you don’t have a ring to measure.

Take a piece of stiff cardboard, plastic or thick wire and wrap it around the finger then mark the exact spot where the ends join. 

With a ruler measure the length of this piece of cardboard or wire.

Read from the chart the ring size.

Note:

1. Do not use a piece of string as this will bend to the shape of your finger. It is best to use a piece of thick cardboard the width of the new ring.

2. After you have measured the length then tape it together and put it on your finger just like a real ring. Make it tight but be sure not to push or squeeze it because you won’t be able to do that with a real ring. Make sure it fits over the knuckle.

3. If you have used a thin piece of wire and your new ring is a wide band you must add some size to allow for this. The reverse may also be true. If you use a wide piece of cardboard but the ring is going to be thin then take a quarter size off.

So now you have a working model and as a further test you can check the measurements on the chart and read off the size.  You must be getting very close if you have been careful.

How accurate can I get measuring my own ring size?

- Abby Seymour would recommend going to a jeweller for a professional true fitting. 

- Measuring your own ring size will never be as accurate as going to a jewellery for a professional fitting. By following the above guide and information you will get a fairly accurate ring size, there may be a slight variant due to the size of the nib on your pen, (if you are using a thick nib - 1mm pen mark this can add 1/2 to a full ring size up) so try to make the smallest mark possible. By using this guide you are agreeing to these conditions and the risk of inaccurate