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US ring size 13½

A US size 13½ ring is 22.60 mm (0.890") across the inside and 71.0 mm (2.80") round. It converts to UK Z+2, EU 71, Japan 30 and Swiss 31. The 1:1 circle below is already set to size 13½: 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 13½22.60 mm · 0.890" inside · 71.0 mm round
Inside diameter22.60 mm
Band wall1.8 mm
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Full chart 19 rows

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Size 13½ and the quarter sizes around it

9 rows
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US ring size 13.5 and quarter sizes within one size either side: inside diameter, difference in mm, circumference, UK and EU sizes
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21.79−0.81 mm68.5Z68
21.99−0.61 mm69.1Z½69
22.20−0.41 mm69.7Z+170
22.40−0.20 mm70.4Z+1½70
22.60—71.0Z+271
22.81+0.20 mm71.6Z+2½72
23.01+0.41 mm72.3Z+372
23.21+0.61 mm72.9Z+3½73
23.42+0.81 mm73.6Z+474

Ordering a size 13½ in different band widths

4 rows
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What size to order for a US size 13.5 finger in narrow, 4–6 mm, 7 mm and wider, and comfort-fit bands
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13½22.60Bands under 4 mm usually fit true to size.
13¾–1422.81–23.01A 4–6 mm band covers more skin and feels snugger: jewellers suggest a quarter to a half size up.
14–14½23.01–23.42Wide and cigar bands grip the whole finger segment: half a size to a full size up.
13–13¼22.20–22.40A domed comfort-fit inside slips over the knuckle more easily: often a quarter to a half size down.

Blank length for a size 13½ band

6 rows
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Length of wire or sheet to cut for a US size 13.5 ring band (22.60 mm inside) in stock 1.0 to 2.5 mm thick, by π × (inside diameter + thickness)
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74.22.919"24.60
74.82.944"25.00
75.72.981"25.60
76.73.018"26.20
77.33.043"26.60
78.93.105"27.60

05 / Field guide

Size 13½,
22.60 mm inside.

Everything about a US 13½: 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 13 and size 14.

Who wears a size 13½

A US 13½ is a large men’s size above the usual 9 to 12 range, also used for men’s thumb rings. Jewellers’ order data puts the most common women’s size at 7 and men’s at 10, so a 13½ is 6.5 sizes above the usual women’s size and 3.5 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 13 (22.20 mm) and 0.41 mm narrower than a 14 (23.01 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 13½ by most of a size.

Size 13½ in the UK, Europe and Japan

A 13½ is 71.0 mm round. UK letters on the BS 6820 scale cover 0.625 mm each with half sizes, and Z+2 runs from 70.94 to 71.56 mm, so a 13½ sits near the bottom of Z+2. If you are on the small side of a 13½, a UK Z+1½ may suit better.

ISO 8653 rounds to the nearest millimetre, so EU 71 covers 70.5 to 71.5 mm and a 13½ lands 0.51 mm into that band. Swiss and Italian sizes subtract 40, giving 31. Japan 30 is 22.7 mm inside, 0.10 mm larger than a US 13½, so Japanese 30 is the nearest match.

Quarter sizes either side

A 13¼ is 22.40 mm and a 13¾ is 22.81 mm, each about 0.2 mm from a 13½: roughly the thickness of two sheets of paper on the diameter. If your ring falls between 13¼ and 13¾ on the 1:1 circle, order a 13½ for a band under 4 mm.

For a 4–6 mm band, jewellers suggest 13¾ to 14; for 7 mm and wider, 14 to 14½; for a comfort-fit inside, 13 to 13¼. Smart-ring kits that include a size 14 sample: Oura Ring 4, Galaxy Ring, Ring AIR.

Making a size 13½ band

The blank length is the circumference of the middle of the band wall: π × (22.60 + thickness). Cut 75.7 mm of 1.5 mm stock or 77.3 mm of 2.0 mm stock, and the finished band has an outside diameter of 25.60 or 26.60 mm. Leave a little extra for filing the joint, and true the band on a mandrel at 13½ after soldering.

Blank = π × (22.60 mm + t) · 1.5 mm → 75.7 mm · 2.0 mm → 77.3 mm

Questions

Answered plainly.

01What is a size 13½ ring in mm?+

A US size 13½ ring is 22.60 mm (0.890") across the inside, with an inside circumference of 71.0 mm (2.80").

02What is a US size 13½ in UK and EU sizes?+

US 13½ is UK Z+2 and EU (ISO 8653) 71. It is also Japan 30 and Swiss 31.

03How much bigger is a size 14 than a size 13½?+

A size 14 is 0.41 mm wider inside (23.01 against 22.60 mm) and 1.28 mm longer round.

04How long a blank do I cut for a size 13½ ring?+

75.7 mm for 1.5 mm thick stock and 77.3 mm for 2.0 mm, from π × (22.60 mm + thickness).

05Should I order a size 13½ for a wide band?+

For a band 7 mm or wider, jewellers suggest 14 to 14½; for 4–6 mm, 13¾ to 14. Under 4 mm, a 13½ fits true to size.

Ring sizesUS · inside Ø mm

Carat sizes

Necklace lengths