Ring size 11.5 in mm
A US size 11.5 ring has an inner diameter of 21 mm and a circumference of 66 mm (EU 66). UK W½.
| Diameter, mm | Circumference, mm | US | UK |
|---|---|---|---|
| 14.1 | 44.3 | 3 | F |
| 14.5 | 45.6 | 3.5 | G |
| 14.9 | 46.8 | 4 | H |
| 15.3 | 48.1 | 4.5 | I |
| 15.7 | 49.3 | 5 | J½ |
| 16.1 | 50.6 | 5.5 | K½ |
| 16.5 | 51.8 | 6 | L½ |
| 16.9 | 53.1 | 6.5 | M½ |
| 17.3 | 54.3 | 7 | N½ |
| 17.7 | 55.6 | 7.5 | O½ |
| 18.1 | 56.9 | 8 | P½ |
| 18.5 | 58.1 | 8.5 | Q½ |
| 18.9 | 59.4 | 9 | R½ |
| 19.4 | 60.9 | 9.5 | S½ |
| 19.8 | 62.2 | 10 | T½ |
| 20.2 | 63.5 | 10.5 | U½ |
| 20.6 | 64.7 | 11 | V½ |
| 21 | 66 | 11.5 | W½ |
| 21.4 | 67.2 | 12 | X½ |
| 21.8 | 68.5 | 12.5 | Z |
| 22.2 | 69.7 | 13 | Z+1 |
Wrap a thread or paper strip around the base of the finger, mark where it meets and measure the length – that is the circumference. Or measure the inner diameter of a ring you own. Measure in the evening when fingers are warm.
Enter measurements in the converter ("From measurements") and all your sizes collect here. The data stays in this browser.
- Diameter
- 21 mm
- Circumference
- 66 mm
- ISO / EU
- 66
- Typically
- larger men's fingers
Wide band – half a size up
Bands wider than 6 mm feel tighter: choose 21.5 mm instead of 21. Fingers shrink in the cold and swell in the heat: measure at room temperature, in the evening.
A ring should slide over the knuckle with slight resistance and not spin on the finger.
Frequently asked
01Ring size 11.5 in mm
A US size 11.5 ring has an inner diameter of 21 mm and a circumference of 66 mm (EU 66). UK W½.
02What is US size 11.5 in mm?
21 mm diameter, 66 mm circumference.
03What is the circumference of a US 11.5?
66 mm – EU size 66.
Check another size
Brand charts can differ by up to half a size.