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cm to Ring Size Converter

Created by Kenneth Alambra
Reviewed by Komal Rafay
Last updated: Jan 18, 2024


Use this cm-to-ring size converter to quickly find out your (or your friend's or partner's) ring size with just a strip of paper and a ruler with centimeter markings. Finding the correct ring size is crucial to maintain comfort on the wearer's fingers. We don't want rings that are too tight which can hinder proper blood flow through our fingers, and we also don't want loose rings because we might lose them in everyday use.

In this conversion calculator, you will discover the following:

  • How to measure your ring size with this cm-to-ring size converter;
  • How to use the cm-to-ring size conversion chart;
  • A list of our other ring-sizing tools you can use; and
  • Some conversion examples you can use as a guide.

What are you waiting for? Grab a piece of paper, scissors, a pen, and a ruler, and proceed to the next section of this text. 😊

How to measure your ring size with this cm-to-ring size converter

Measuring your finger is very straightforward with a thin and narrow measuring tape. But not all of us have that in our homes.

We could cut a narrow strip of paper so we can wrap it around our finger in question. Make sure to wrap around the knuckle area where the ring should pass to make sure the ring will fit. With a pen, mark where the end of the strip of paper overlaps itself. Then measure this part of the paper using your ruler, and don't forget to read the length in centimeters!

Here is an illustration of how to do it on your right ring finger:

Illustrative guide on how to measure a finger using a strip of paper and a ruler.

Let's say you measured a length of around 5.6 centimeters. All you have to do now is find the next closest inside circumference value in our converter. In this case, we have there 5.645 cm. Select that value, and our cm-to-ring size converter will give you 7 3/4 (for US & Canada ring size) and P 1/2 (for UK & Australia ring size).

You can also try selecting 5.715 cm for the inside circumference if you need your closest equivalent ring sizes in the other sizing standards. It just so happened that 7 3/4 US and different US ring sizes don't have equivalent sizes in other countries.

Use this cm-to-ring size converter for circumference conversions easily by following the steps above. But you can also quickly measure another ring's diameter and select its closest value in our converter's inside diameter selection list to find its equivalent ring size.

How to use the cm-to-ring size conversion chart

You can also use this cm-to-ring size conversion chart for a quick overview of the different equivalent ring sizes we use in our tool:

Inside Diameter (cm)

Inside Circumference (cm)

Sizes

UK & Australia

US & Canada

France

Germany

Japan

Switzerland

1.153

3.622

_

0

_

_

_

_

1.195

3.754

A

1/2

_

_

_

_

1.237

3.886

B

1

_

_

1

_

1.278

4.015

C

1 1/2

_

_

_

_

1.321

4.150

D

2

41 1/2

13 1/2

2

1 1/2

1.361

4.276

E

2 1/2

42 3/4

13 3/4

3

2 3/4

1.405

4.414

F

3

44

14

4

4

1.436

4.511

G

3 3/8

45 1/4

_

5

5 1/4

1.445

4.540

G 1/4

3 1/2<

_

14 1/2

_

_

1.456

4.574

G 1/2

3 5/8

_

_

6

_

1.465

4.602

H

3 3/4

46 1/2

_

_

6 1/2

1.486

4.668

H 1/2

4

_

15

7

_

1.504

4.725

I

4 1/4

47 3/4

_

_

7 3/4

1.527

4.797

I 1/2

4 1/2

_

15 1/4

8

_

1.540

4.838

J

4 5/8

49

15 1/2

_

9

1.570

4.932

J 1/2

5

_

15 3/4

9

_

1.580

4.964

K

5 1/8

50

_

_

10

1.600

5.027

K 1/2

5 3/8

_

10

_

1.610

5.058

L

5 1/2

51 3/4

16

_

11 3/4

1.651

5.187

M

6

52 3/4

16 1/2

12

12 3/4

1.692

5.316

N

6 1/2

54

17

13

14

1.735

5.451

O

7

55 1/4

17 1/4

14

15 1/4

1.775

5.576

P

7 1/2

56 1/2

17 3/4

15

16 1/2

1.819

5.715

Q

8

57 3/4

18

16

17 3/4

1.853

5.821

Q 3/4

8 1/2

_

18 1/2

17

_

1.861

5.847

R

8 5/8

59

_

_

19

1.889

5.934

R 3/4

9

_

19

18

_

1.910

6.000

S

9 1/8

60 1/4

_

_

20 1/4

1.941

6.098

S 3/4

9 1/2

_

19 1/2

19

_

1.951

6.129

T

9 5/8

61 1/2

_

_

21 1/2

1.984

6.233

T 1/2

10

_

20

20

_

2.002

6.289

U

10 1/4

62 3/4

_

21

22 3/4

2.020

6.346

U 1/2

10 1/2

_

20 1/4

22

_

2.032

6.384

V

10 5/8

63

_

_

23 3/4

2.068

6.497

V 1/2

11

_

20 3/4

23

_

2.076

6.522

W

11 1/8

65

_

_

25

2.108

6.622

W 3/4

11 1/2

_

21

24

_

2.118

6.654

X

11 5/8

66 1/4

_

_

26 1/4

2.149

6.751

Y

12

67 1/2

21 1/4

25

27 1/2

2.189

6.877

Z

12 1/2

68 3/4

21 3/4

26

28 3/4

2.233

7.015

Z+1

13

_

22

27

_

Our other ring-sizing tools you can use

You can also check our other ring-sizing conversion calculators listed below to learn more:

FAQ

How do I measure my finger's ring size?

To measure your finger's ring size:

  1. Wrap a strip of paper (or a string) around the finger.
  2. Using a pen, mark where it overlaps over itself.
  3. Take a ruler and measure the length of the paper until the marking. This measurement is your finger's circumference. Divide it by π (or approximately 3.1415) to get the equivalent diameter of your finger.
  4. Check your ring supplier's guide for your ring size.

What ring size measures 6 cm in circumference?

The 9 1/8 US ring size has an inside circumference of 6 centimeters. This ring size is equivalent to 9 1/8 Canada ring size, S ring size in UK and Australia, 60 1/4 in France and Russia, and 20 1/4 in Switzerland.

Kenneth Alambra
Measurements
Inside circumference
Select...
cm
Inside diameter
Select...
cm
Ring size equivalents
US & Canada
Select...
UK & Australia
Select...
France & Russia
Select...
Germany
Select...
Switzerland
Select...
Japan
Select...
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