Ring size by country
Different countries use completely different scales. Here's which system each uses — and a converter so the numbers actually line up.
Your size is US 7 (UK N½, EU 54).
Measurement check Exact table match
Measurement check Standard chart conversion; final fit still depends on band width and knuckle shape. Confirm with a printable or physical sizer before ordering an expensive ring.
- US
- 7
- UK
- N½
- EU / ISO
- 54
- Japan
- 14
- CH / IT / ES
- 14
- Inner diameter, millimetres
- 17.32
- Circ mm
- 54.4
Why this size?
Your input maps to US 7 — UK N½, EU 54, JP 14, Ø 17.32 mm.
Calculated dimensions are rounded chart values, not a measured accuracy guarantee. Ruler placement, print scale, screen calibration and the finger can change the result. Confirm with a physical sizer before ordering.
More options
Choose the fit problem and get the safest next step before resizing, replacing or buying another ring.
Too tight or stuck Too loose or spinning Wide band or comfort-fit Non-resizable or brand ring
| US | UK | EU | JP | CH | Inner diameter, millimetres | Circ mm |
|---|---|---|---|---|---|---|
| 3 | F½ | 44 | 4 | 4 | 14.07 | 44.2 |
| 3.5 | G½ | 45 | 5 | 5 | 14.48 | 45.5 |
| 4 | H½ | 47 | 7 | 7 | 14.88 | 46.8 |
| 4.5 | I½ | 48 | 8 | 8 | 15.29 | 48.0 |
| 5 | J½ | 49 | 9 | 9 | 15.70 | 49.3 |
| 5.5 | K½ | 51 | 10 | 11 | 16.10 | 50.6 |
| 6 | L½ | 52 | 12 | 12 | 16.51 | 51.9 |
| 6.5 | M½ | 53 | 13 | 13 | 16.92 | 53.1 |
| 7 | N½ | 54 | 14 | 14 | 17.32 | 54.4 |
| 7.5 | O½ | 56 | 15 | 16 | 17.73 | 55.7 |
| 8 | P½ | 57 | 16 | 17 | 18.14 | 57.0 |
| 8.5 | Q½ | 58 | 17 | 18 | 18.54 | 58.3 |
| 9 | R½ | 60 | 18 | 20 | 18.95 | 59.5 |
| 9.5 | S½ | 61 | 19 | 21 | 19.35 | 60.8 |
| 10 | T½ | 62 | 20 | 22 | 19.76 | 62.1 |
| 10.5 | U½ | 63 | 22 | 23 | 20.17 | 63.4 |
| 11 | V½ | 65 | 23 | 25 | 20.57 | 64.6 |
| 11.5 | W½ | 66 | 24 | 26 | 20.98 | 65.9 |
| 12 | Y | 67 | 25 | 27 | 21.39 | 67.2 |
| 12.5 | Z | 68 | 26 | 28 | 21.79 | 68.5 |
| 13 | Z½ | 70 | 27 | 30 | 22.20 | 69.7 |
Which system each country uses
| Country / region | System | Based on | Note |
|---|---|---|---|
| USA, Canada, Mexico | US numeric (½ steps) | Inner diameter | The number is set by inner diameter in inches. |
| UK, Ireland, Australia, NZ, South Africa | Letters A–Z (+½) | Circumference | Same alphabetic scale; US 7 = UK N½. |
| France, Germany, EU (ISO 8653) | EU / ISO number | Circumference (mm) | The size number IS the inner circumference in mm. |
| Japan | JP number | Lookup (JIS) | Own scale; no half sizes, skips some numbers. |
| Switzerland, Italy, Spain | Number | Circumference − 40 | Size ≈ circumference in mm minus 40. |
| India | Indian number | Lookup | Own numeric scale; treat conversions as approximate. |
| China | HK number or ISO mm | Mixed | Two conventions coexist; order by mm when possible. |
The cleanest, most universal measurement is millimetres: see the full chart with diameter and circumference for every size.
Related sizing tools
If you are comparing more than ring systems, these tools use the same measurement-first approach:
- shoe size converter (opens in a new tab) — convert US, UK, EU and CM shoe sizes by foot length.
- brand-to-brand clothing size converter (opens in a new tab) — compare supported clothing brands from a size you already know.
Frequently asked questions
Which ring size system does the US use?
The US (and Canada and Mexico) use a numeric system in half-size steps based on the ring’s inner diameter in inches.
What ring size system does Europe use?
Most of continental Europe uses the EU/ISO 8653 system, where the size number equals the inner circumference in millimetres (so EU 54 = 54 mm).
Why are UK ring sizes letters?
The UK, Ireland and Australia share an alphabetic scale (A–Z with half sizes) based on circumference. US whole sizes usually fall on a UK half letter — for example US 7 = UK N½.