Circumference (mm) to Diameter (mm) Ring Size (Standard Fit)
1 Circumference value = 0.31831 Diameter value · profile-dependent conversion · context: size system and fit profile
Direct Answer
1 Circumference value equals 0.31831 Diameter value
This result depends on the selected profile context: size system and fit profile.
For 4 Circumference value, this profile returns 1.27324 Diameter value.
Converter Calculator
1 Circumference (mm) value =
0.31831 Diameter (mm) value
Explanation
Circumference (mm) converts to Diameter (mm) by normalizing to ring diameter in millimeters, then remapping to the target system. Fit profile fixed: Standard Fit.
From Circumference value to Diameter value, results depend on the selected size system and fit profile and stay consistent with that profile across table rows and calculator input.
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Keep the same profile in both directions to avoid mixing lookup systems that use different size mappings.
Common Conversion Values
| Circumference (mm) value | Diameter (mm) value |
|---|---|
| 4 | 1.27324 |
| 5 | 1.591549 |
| 6 | 1.909859 |
| 7 | 2.228169 |
| 8 | 2.546479 |
| 9 | 2.864789 |
| 10 | 3.183099 |
| 11 | 3.501409 |
| 12 | 3.819719 |
| 13 | 4.138029 |