Measure ring size at homeCM conversion
How to measure ring size at home in cm
Centimeters are easy to read, but ring charts usually work in millimeters. Multiply centimeters by 10 before choosing a size.
Calibrate your screen
Place a real bank card on your screen. Align its top-left corner with the virtual card, then use the slider until the virtual card's left vertical edge matches exactly.
Standard bank card short edge: 53.98 mm. No camera, no upload, no card number needed.
Measure finger circumference
Wrap paper or string around the finger base, mark the overlap, then lay it straight on the ruler and drag the marker so the red line meets the end.
If your measurement falls between two sizes, choose the larger size. For wide bands or fingers that swell easily, choose a slightly larger size.
Quick answer: How to measure ring size at home in cm
Measure the finger circumference in centimeters, multiply by 10 to get millimeters, then choose the first chart row equal to or larger than your result.
- Measure the finger circumference in centimeters.
- Multiply the value by 10 to convert cm to mm.
- Compare the millimeter result with the chart.
CM to ring size calculator
Enter the circumference in centimeters. The calculator converts it to millimeters first.
If your measurement falls between two sizes, choose the larger size.
How to measure your finger
5.44 cm equals 54.4 mm before ring size conversion.
CM reading
Measure the finger circumference in centimeters.
Wrap and mark
Multiply the value by 10 to convert cm to mm.
Choose the larger row
Choose the larger size if the value falls between two rows.
Measure finger circumference in cm
Wrap the strip around the finger base and read the overlap length in centimeters. This value is circumference, not diameter.
CM to mm conversion
Ring charts are usually built around millimeters. Move the decimal one place to the right: 5.44 cm becomes 54.4 mm.
Examples: 5 cm, 6 cm, 7 cm
5.0 cm is a small ring size range, 6.0 cm is around US 9 to 9.25, and 7.0 cm is near the largest common rows in this chart.
Ring size chart for this method
This table shows common conversion rows. If your measurement sits between two rows, use the larger recommended size for purchase.
| Circumference mm | Diameter mm | ISO / EU | US / CA | UK / AU | JP / CN | IT / ES / CH | RU |
|---|---|---|---|---|---|---|---|
| 44.2 | 14.1 | 44 | 3 | F | 4 | 4 | 14 |
| 45.5 | 14.5 | 46 | 3.5 | G | 5 | 5¼ | 14.5 |
| 46.8 | 14.9 | 47 | 4 | H | 7 | 6½ | 15 |
| 48.0 | 15.3 | 48 | 4.5 | I | 8 | 7¾ | 15.25 |
| 49.3 | 15.7 | 49 | 5 | J½ | 9 | 9 | 15.75 |
| 50.6 | 16.1 | 50.5 | 5.5 | K½ | 10 | 10¼ | 16.25 |
| 51.9 | 16.5 | 52 | 6 | L½ | 12 | 11½ | 16.5 |
| 53.1 | 16.9 | 53 | 6.5 | M½ | 13 | 12¾ | 17 |
| 54.4 | 17.3 | 54.5 | 7 | N½ | 14 | 14 | 17.25 |
| 55.7 | 17.7 | 56 | 7.5 | O½ | 15 | 15¼ | 17.75 |
| 57.0 | 18.1 | 57 | 8 | P½ | 16 | 16½ | - |
| 58.3 | 18.6 | 58.5 | 8.5 | Q½ | 17 | 17¾ | 18.5 |
| 59.5 | 18.9 | 60 | 9 | R½ | 18 | 19 | 19 |
| 60.8 | 19.4 | 61 | 9.5 | S½ | 19 | 20¼ | 19.5 |
| 62.1 | 19.8 | 62 | 10 | T½ | 20 | 21½ | 19.75 |
| 63.4 | 20.2 | 63.5 | 10.5 | U½ | 22 | 22¾ | - |
| 64.6 | 20.6 | 65 | 11 | V½ | 23 | 24 | 20.75 |
| 65.9 | 21.0 | 66 | 11.5 | W½ | 24 | 25¼ | 21 |
| 67.2 | 21.4 | 67.5 | 12 | X½ | 25 | 26½ | 21.5 |
| 68.5 | 21.8 | 69 | 12.5 | Z | 26 | 27¾ | 21.75 |
| 69.7 | 22.2 | 70 | 13 | - | 27 | 29 | 22 |
Conversion examples
| Input | Millimeters | Recommendation |
|---|---|---|
| 5.44 cm | 54.4 mm | US 7 / EU 54.5 |
| 5.70 cm | 57.0 mm | US 8 / EU 57 |
| 6.08 cm | 60.8 mm | US 9.5 / EU 61 |
FAQ
How do I convert cm to ring size?
Multiply the centimeter circumference by 10 to get millimeters, then use the chart or calculator to choose the next larger listed row.
Is 6 cm a ring circumference or diameter?
For at-home finger measurement, 6 cm should mean circumference. A 6 cm diameter would be far outside normal ring sizing.
Should I size up if I am between two ring sizes?
Yes. For online buying, choose the larger listed size when your measurement falls between two rows. A ring that is slightly loose is easier to adjust than one that will not pass the knuckle.
Is circumference or diameter better for ring sizing?
Circumference is safer for measuring a finger at home. Diameter is useful when measuring an existing ring, but it should be converted back to circumference before choosing a purchase size.
When should I measure my finger?
Measure near the end of the day at normal body temperature. Cold hands can shrink and hot weather can make fingers swell.