💍 Jewellery
UK X½ to US
Converting a UK ring size of X½ gives US 12, based on an inner circumference of about 67.2 mm. The complete cross-system chart is below.
UK X½ = US 12
Inner circumference ≈ 67.2 mm · diameter ≈ 21.4 mm · EU/ISO 67
Full cross-system equivalents for this ring size:
| US | UK | EU | JP | Circ (mm) | Diam (mm) |
|---|---|---|---|---|---|
| 10.5 | U½ | 63 | 22 | 63.4 | 20.2 |
| 11 | V½ | 65 | 23 | 64.6 | 20.6 |
| 11.5 | W½ | 66 | 24 | 65.9 | 21.0 |
| 12 | X½ | 67 | 25 | 67.2 | 21.4 |
| 12.5 | Y½ | 68 | 26 | 68.5 | 21.8 |
| 13 | Z½ | 70 | 27 | 69.7 | 22.2 |
⚠️ UK letters vary by jeweller: half-letter conventions differ slightly between brands. The EU/ISO number equals the inner circumference in mm, so it's the most reliable cross-check. If between sizes, order the larger.
Need a different size? Use the live ring size converter to convert any value, including a mm measurement.
ⓘ Affiliate links below. As an Amazon Associate we earn from qualifying purchases at no extra cost to you.
★ Top pick · Recommended on Amazon
Ring Sizer Tool (Set)
Reusable finger-gauge set to measure your true size at home before ordering.
View on Amazon →Recommended on Amazon
Digital Caliper
Measure an existing ring's inner diameter in mm to the tenth for an exact match.
View on Amazon →Recommended on Amazon
Men's Tungsten Band
Larger sizes are often men's — durable tungsten bands in a full size range.
View on Amazon →