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US ring size 9

A US size 9 ring is 18.95 mm (0.746") across the inside and 59.5 mm (2.34") round. It converts to UK R½, EU 60, Japan 19 and Swiss 19.5. The 1:1 circle below is already set to size 9: 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 918.95 mm · 0.746" inside · 59.5 mm round
Inside diameter18.95 mm
Band wall1.8 mm
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Full chart 19 rows

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Size 9 and the quarter sizes around it

9 rows
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US ring size 9 and quarter sizes within one size either side: inside diameter, difference in mm, circumference, UK and EU sizes
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18.13−0.81 mm57.0P½57
18.34−0.61 mm57.6Q58
18.54−0.41 mm58.2Q½58
18.74−0.20 mm58.9R59
18.95—59.5R½60
19.15+0.20 mm60.2S60
19.35+0.41 mm60.8S½61
19.55+0.61 mm61.4T61
19.76+0.81 mm62.1T½62

Ordering a size 9 in different band widths

4 rows
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What size to order for a US size 9 finger in narrow, 4–6 mm, 7 mm and wider, and comfort-fit bands
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918.95Bands under 4 mm usually fit true to size.
9¼–9½19.15–19.35A 4–6 mm band covers more skin and feels snugger: jewellers suggest a quarter to a half size up.
9½–1019.35–19.76Wide and cigar bands grip the whole finger segment: half a size to a full size up.
8½–8¾18.54–18.74A domed comfort-fit inside slips over the knuckle more easily: often a quarter to a half size down.

Blank length for a size 9 band

6 rows
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Length of wire or sheet to cut for a US size 9 ring band (18.95 mm inside) in stock 1.0 to 2.5 mm thick, by π × (inside diameter + thickness)
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62.72.467"20.95
63.32.492"21.35
64.22.529"21.95
65.22.566"22.55
65.82.591"22.95
67.42.652"23.95

05 / Field guide

Size 9,
18.95 mm inside.

Everything about a US 9: 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 8½ and size 9½.

Who wears a size 9

A US 9 is where the ranges meet: a larger women’s size and the start of the men’s 9 to 12 range. Jewellers’ order data puts the most common women’s size at 7 and men’s at 10, so a 9 is 2 sizes above the usual women’s size and 1 size below 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 8½ (18.54 mm) and 0.41 mm narrower than a 9½ (19.35 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 9 by most of a size.

Size 9 in the UK, Europe and Japan

A 9 is 59.5 mm round. UK letters on the BS 6820 scale cover 0.625 mm each with half sizes, and R½ runs from 59.06 to 59.69 mm, so a 9 sits near the top of R½. If you are on the large side of a 9, a UK S may suit better.

ISO 8653 rounds to the nearest millimetre, so EU 60 covers 59.5 to 60.5 mm and a 9 lands 0.02 mm into that band. Swiss and Italian sizes subtract 40, giving 19.5. Japan 19 is 19.0 mm inside, 0.05 mm larger than a US 9, so Japanese 19 is the nearest match.

Quarter sizes either side

A 8¾ is 18.74 mm and a 9¼ is 19.15 mm, each about 0.2 mm from a 9: roughly the thickness of two sheets of paper on the diameter. If your ring falls between 8¾ and 9¼ on the 1:1 circle, order a 9 for a band under 4 mm.

For a 4–6 mm band, jewellers suggest 9¼ to 9½; for 7 mm and wider, 9½ to 10; for a comfort-fit inside, 8½ to 8¾. Smart-ring kits that include a size 9 sample: Oura Ring 4, Galaxy Ring, Ring AIR.

Making a size 9 band

The blank length is the circumference of the middle of the band wall: π × (18.95 + thickness). Cut 64.2 mm of 1.5 mm stock or 65.8 mm of 2.0 mm stock, and the finished band has an outside diameter of 21.95 or 22.95 mm. Leave a little extra for filing the joint, and true the band on a mandrel at 9 after soldering.

Blank = π × (18.95 mm + t) · 1.5 mm → 64.2 mm · 2.0 mm → 65.8 mm

Questions

Answered plainly.

01What is a size 9 ring in mm?+

A US size 9 ring is 18.95 mm (0.746") across the inside, with an inside circumference of 59.5 mm (2.34").

02What is a US size 9 in UK and EU sizes?+

US 9 is UK R½ and EU (ISO 8653) 60. It is also Japan 19 and Swiss 19.5.

03How much bigger is a size 9½ than a size 9?+

A size 9½ is 0.41 mm wider inside (19.35 against 18.95 mm) and 1.28 mm longer round.

04How long a blank do I cut for a size 9 ring?+

64.2 mm for 1.5 mm thick stock and 65.8 mm for 2.0 mm, from π × (18.95 mm + thickness).

05Should I order a size 9 for a wide band?+

For a band 7 mm or wider, jewellers suggest 9½ to 10; for 4–6 mm, 9¼ to 9½. Under 4 mm, a 9 fits true to size.

Ring sizesUS · inside Ø mm

Carat sizes

Necklace lengths