Ring Size Chart & Ring Sizer Tool

Finding the ideal ring size is crucial, whether you’re buying an engagement ring, a fashion statement piece, or a smart wearable like the Oura ring. With so many sizing systems and measurements (US sizes, UK, EU, Japan, millimetres, centimetres, inches), it’s easy to get overwhelmed. Here you will find all about the ring size chart and how to use a printable ring size chart to measure at home. We will ensure that your ring fits comfortably and securely..

Ring Sizer Calculator Ring Size Chart

Measure Your Ring Size with Our Online Ring Sizer

Ring Size in MM, Ring Size in CM, Ring Size in Inches

Ring Sizer in MM

Ring Diameter: 16.50 mm
11mm 23mm

Your size is

US/CA: 6 UK: L
EU: 52 JP: 11
Show Size Chart

Ring Sizer in CM

Ring Diameter: 1.65 cm
1.1cm 2.3cm

Your size is

US/CA: 6 UK: L
EU: 52 JP: 11

Ring Sizer in Inches

Ring Diameter: 0.65 in
0.45in 0.90in

Your size is

US/CA: 6 UK: L
EU: 52 JP: 11
Show Size Chart

Ring Size Diameter & Circumference Chart

Circumference (mm)

Diameter (mm)

US Size

UK Size

44.2

14.1

3

F

47.7

15.2

4

H

51.0

16.2

5

J

54.4

17.3

7

N ½

57.9

18.4

9

R ½

60.8

19.3

10

S
ring size chart

Comprehensive International Ring Size Conversion Chart 

To cater to our global clientele, we've compiled a detailed conversion chart encompassing various international ring sizing standards. This table allows you to easily convert your size across different regions, ensuring you find the perfect match no matter where you are in the world. You can get all the information about the international ring size chart. 

Download Printable Ring Size Chart

Tips for Measuring Your Finger Perfectly

MEASURE AT ROOM TEMPERATURE

Cold shrinks, heat expands.

REPEAT ON MULTIPLE DAYS

Ensure consistency within 1 mm.

USE THIN PAPER OR DENTAL FLOSS

Mark overlap, then lay flat against a ruler.

CONSIDER RING WIDTH

Wider bands (≥ 6 mm) may require up to ½ size larger.

AVOID KNUCKLE ISSUES

Take two measurements: knuckle and base; choose an intermediate size or comfort fit style.

Why Accurate Ring Sizing Matters?

  • Comfort & Wearability: A ring that’s too tight can pinch and restrict blood flow; one that’s too loose risks slipping off and being lost.
  • Professional Standards: Jewellers base prong height, stone settings, and comfort fit designs on precise sizes; inaccurate sizing can compromise the setting.
  • Smart Wearables: Devices like the Oura ring rely on a snug fit to accurately monitor heart rate, temperature, and movement. An improper fit can skew data by up to 15%.
  • Brand-Specific Fit: High-end brands (e.g., Cartier ring size chart) have their unique calibrations; using generic charts may lead to off-by-one-size errors.

Fact: The global average ring size for women is US 6 (16.5 mm diameter), and for men, US 10 (19.8 mm diameter).

Accurate Ring Sizing

How to Measure Ring Size ?

We offer several easy-to-use methods to help you find your ring size from the comfort of your home. For best accuracy, we recommend trying a few different techniques and cross-referencing your results.  

Method 1: The String or Paper Strip Method

This popular method uses simple household items to determine your finger's circumference.  

Materials Needed:

  • A piece of string, ribbon, thread, or a strip of paper (at least 3 inches long and no wider than 1/2 inch)  
  • A pen or marker  
  • A ruler (in millimeters)  

Steps:

  1. Wrap the string or paper strip snugly around the base of the finger you intend to wear the ring on.  
  2. Use a pen to mark the point where the two ends overlap.  
  3. Lay the marked string or paper flat and measure its length in millimeters with your ruler.  
  4. Match this measurement to the "Circumference (mm)" column in our chart above to find your corresponding ring size. If your measurement falls between two sizes, it's generally recommended to choose the larger size.  

Full Tutorial for the String or Paper Strip Method For Ring Size:

Measuring an Existing Ring

Method 2: Measuring an Existing Ring

If you have a ring that already fits comfortably on the desired finger, this method is quick and effective, especially for discreetly finding someone else's size.  

Materials Needed:

  • A ring that fits comfortably on the intended finger  
  • A ruler (in millimeters)  
  • Our printable ring sizer (optional, but recommended for accuracy)  

Steps:

  1. Place the existing ring on a flat surface.  
  2. Measure the inside diameter of the ring in millimeters (a straight line across the center of the inner circle).  
  3. Alternatively, place the ring over the circles on our printable ring sizer, matching the inside of the ring to the circle that fits perfectly.  
  4. Use the "Inside Diameter (mm)" column in our chart to find your corresponding ring size.  

Method 3: Ring Size Printable Chart

Our printable ring sizer offers a convenient way to measure your finger or an existing ring directly.  

Materials Needed:

  • Scissors  
  • A printer
  • Our printable ring sizer PDF 

Steps:

1. Crucially, print the PDF at 100% scale to ensure accuracy. Do not select "fit to page" or similar options.

2. Follow the instructions on the printed guide. This may involve cutting out a paper sizer to wrap around your finger or placing an existing ring over the pre-sized circles. 

3. Match your measurement to the chart provided on the printable sizer or our main conversion chart. 

Ring Size Printable Chart

Ring Size Chart in CM, MM & Inches

Circumference

Ring size chart in mm

Ring Size Chart in cm

Ring Size Chart in inches

49.3 mm

15.7 mm

1.57 cm

0.62 in

51.9 mm

16.5 mm

1.65 cm

0.65 in

54.4 mm

17.3 mm

1.73 cm

0.68 in

57.0 mm

18.1 mm

1.81 cm

0.71 in

59.5 mm

18.9 mm

1.89 cm

0.74 in

62.1 mm

19.8 mm

1.98 cm

0.78 in

(Full ring size diameter chart from US 3 to 13 available in the downloadable PDF.)

US Ring Size Chart & Conversion

The US ring size chart ranges from size 3 (14.1 mm) to 13 (22.2 mm) in ¼-size increments (~0.4 mm per increment). Below is a simplified table.

US Size

Diameter (mm)

Circumference (mm)

3

14.1

44.3

4

14.9

46.8

5

15.7

49.3

6

16.5

51.9

7

17.3

54.4

8

18.1

57.0

9

18.9

59.5

10

19.8

62.1

Conversion Fact: A ¼ US size change equals approximately 0.4 mm in diameter and 1.26 mm in circumference².

Ring Size Charts FAQs

A ring size chart is a tool used to determine the appropriate ring size based on different measurement systems such as the US, UK, European, Asian, and international standards. It typically includes diameter, circumference, and size numbers in millimeters (mm), centimeters (cm), or inches. 

  • US: Numbers from 3 to 13.5 (including half sizes).
  • UK: Uses letters (e.g., A to Z+).
  • European (EU): Based on circumference in millimeters (e.g., 44–70 mm).
  • Japan: Numbered 1–27.

  • Diameter in mm: Measures the inner diameter of the ring (e.g., 16.5 mm).
  • Circumference in mm or cm: The length around the finger. For example:
    • 5.7 cm (57 mm) ≈ US size 8
    • 6.2 cm (62 mm) ≈ US size 10

A ring with a 16.5 mm diameter corresponds approximately to:

  • US size: 6
  • UK size: L
  • EU size: 52

  • Use a plastic or metal ring sizer for best accuracy.
  • If online, use an actual-size ring size chart on screen or a printable ring size chart.
  • Visit a jewelry store for professional sizing if unsure.

No, the ring sizing system is the same for men and women. However, men tend to wear larger sizes, usually ranging from 8 to 12, while women generally wear between size 5 to 8.

It’s best to size up rather than down, especially for rings that are wider or if your hands swell during the day.

A ring size conversion chart lets you convert your size between different regions. For example:
US size 7 = UK size N = EU size 54.4 mm = Japan size 14

Yes. Although most charts use mm or cm, you can measure your finger’s circumference in inches and convert it:

  • 2.25 inches ≈ US size 7.5
  • 2.5 inches ≈ US size 10

Yes! Many websites offer but we are providing the best online ring size chart through which you can get all the information about every country.

  • Free ring size printable charts
  • Ring sizing apps or AR tools

  • Diameter: The straight-line distance across the inside of the ring.
  • Circumference: The full distance around the finger or inside of the ring.
  • Formula: Circumference = Diameter × π (3.14)

Oura Ring provides a custom size chart specific to their smart rings. They also ship a free sizing kit with plastic samples so you can try before buying.

This refers to a chart that displays ring sizes at their true physical scale, which allows you to directly place a ring or finger on the screen/paper for accurate sizing. Make sure your screen or printout is not scaled incorrectly.

  • Download the chart as a PDF or an image.
  • Open with a PDF reader or print from an image viewer.
  • Ensure "Scale: 100%" or "No scaling" in the print settings.
  • Check the ruler printed on the chart for accuracy.

Cartier size 54 = 54 mm circumference ≈ US size 7.

This usually refers to mechanical O-rings (not jewelry). But some people mistakenly search this when they mean Oura Ring size chart or regular ring sizing.

Yes. Many printable ring size charts include a paper strip ring sizer that you cut out and wrap around your finger. Just make sure it’s printed to scale.

Use one of these methods:

  • Interactive ring size chart on screen (matches your ring to virtual size).
  • Upload a picture of your finger next to a ruler (some tools estimate from this).
  • Order a free ring sizer or sizing kit from a jeweler.