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US ring size 11½

A US size 11½ ring is 20.98 mm (0.826") across the inside and 65.9 mm (2.59") round. It converts to UK W½, EU 66, Japan 25 and Swiss 26. The 1:1 circle below is already set to size 11½: lay a ring on it to check yours.

Try

Lay a ring that fits flat on the circle and size the red line until it just touches the inside edge of the band all the way round: on a phone, slide sideways anywhere on the stage or hold the buttons below; on a computer, drag the edge, scroll or press ← →. The gold ring is the band’s wall: don’t match its outside.

US 11½20.98 mm · 0.826" inside · 65.9 mm round
Inside diameter20.98 mm
Band wall1.8 mm
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Full chart 19 rows

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Size 11½ and the quarter sizes around it

9 rows
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US ring size 11.5 and quarter sizes within one size either side: inside diameter, difference in mm, circumference, UK and EU sizes
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20.16−0.81 mm63.3U½63
20.37−0.61 mm64.0V64
20.57−0.41 mm64.6V½65
20.77−0.20 mm65.3W65
20.98—65.9W½66
21.18+0.20 mm66.5X67
21.38+0.41 mm67.2X½67
21.59+0.61 mm67.8Y½68
21.79+0.81 mm68.5Z68

Ordering a size 11½ in different band widths

4 rows
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What size to order for a US size 11.5 finger in narrow, 4–6 mm, 7 mm and wider, and comfort-fit bands
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11½20.98Bands under 4 mm usually fit true to size.
11¾–1221.18–21.38A 4–6 mm band covers more skin and feels snugger: jewellers suggest a quarter to a half size up.
12–12½21.38–21.79Wide and cigar bands grip the whole finger segment: half a size to a full size up.
11–11¼20.57–20.77A domed comfort-fit inside slips over the knuckle more easily: often a quarter to a half size down.

Blank length for a size 11½ band

6 rows
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Length of wire or sheet to cut for a US size 11.5 ring band (20.98 mm inside) in stock 1.0 to 2.5 mm thick, by π × (inside diameter + thickness)
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69.02.718"22.98
69.72.743"23.38
70.62.780"23.98
71.62.817"24.58
72.22.842"24.98
73.82.904"25.98

05 / Field guide

Size 11½,
20.98 mm inside.

Everything about a US 11½: what it measures, who usually wears it, how it converts in each country, the quarter sizes around it and what to order for wide bands. Neighbouring sheets: size 11 and size 12.

Who wears a size 11½

A US 11½ is squarely in the men’s range (most men wear 9 to 12), and a common thumb-ring size for women. Jewellers’ order data puts the most common women’s size at 7 and men’s at 10, so a 11½ is 4.5 sizes above the usual women’s size and 1.5 sizes above the usual men’s size. The same finger is often a quarter to half size larger on the dominant hand.

It is 0.41 mm wider inside than a 11 (20.57 mm) and 0.41 mm narrower than a 12 (21.38 mm). On the circumference that is 1.28 mm per half size, which is why a strip of string, stretching a couple of millimetres as you pull it snug, can misread a 11½ by most of a size.

Size 11½ in the UK, Europe and Japan

A 11½ is 65.9 mm round. UK letters on the BS 6820 scale cover 0.625 mm each with half sizes, and W½ runs from 65.31 to 65.94 mm, so a 11½ sits near the top of W½. If you are on the large side of a 11½, a UK X may suit better.

ISO 8653 rounds to the nearest millimetre, so EU 66 covers 65.5 to 66.5 mm and a 11½ lands 0.40 mm into that band. Swiss and Italian sizes subtract 40, giving 26. Japan 25 is 21.0 mm inside, 0.02 mm larger than a US 11½, so Japanese 25 is the nearest match.

Quarter sizes either side

A 11¼ is 20.77 mm and a 11¾ is 21.18 mm, each about 0.2 mm from a 11½: roughly the thickness of two sheets of paper on the diameter. If your ring falls between 11¼ and 11¾ on the 1:1 circle, order a 11½ for a band under 4 mm.

For a 4–6 mm band, jewellers suggest 11¾ to 12; for 7 mm and wider, 12 to 12½; for a comfort-fit inside, 11 to 11¼. Smart-ring kits that include a size 12 sample: Oura Ring 4, Galaxy Ring, Ring AIR.

Making a size 11½ band

The blank length is the circumference of the middle of the band wall: π × (20.98 + thickness). Cut 70.6 mm of 1.5 mm stock or 72.2 mm of 2.0 mm stock, and the finished band has an outside diameter of 23.98 or 24.98 mm. Leave a little extra for filing the joint, and true the band on a mandrel at 11½ after soldering.

Blank = π × (20.98 mm + t) · 1.5 mm → 70.6 mm · 2.0 mm → 72.2 mm

Questions

Answered plainly.

01What is a size 11½ ring in mm?+

A US size 11½ ring is 20.98 mm (0.826") across the inside, with an inside circumference of 65.9 mm (2.59").

02What is a US size 11½ in UK and EU sizes?+

US 11½ is UK W½ and EU (ISO 8653) 66. It is also Japan 25 and Swiss 26.

03How much bigger is a size 12 than a size 11½?+

A size 12 is 0.41 mm wider inside (21.38 against 20.98 mm) and 1.28 mm longer round.

04How long a blank do I cut for a size 11½ ring?+

70.6 mm for 1.5 mm thick stock and 72.2 mm for 2.0 mm, from π × (20.98 mm + thickness).

05Should I order a size 11½ for a wide band?+

For a band 7 mm or wider, jewellers suggest 12 to 12½; for 4–6 mm, 11¾ to 12. Under 4 mm, a 11½ fits true to size.

Ring sizesUS · inside Ø mm

Carat sizes

Necklace lengths