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US ring size 4

A US size 4 ring is 14.88 mm (0.586") across the inside and 46.8 mm (1.84") round. It converts to UK H½, EU 47, Japan 7 and Swiss 7. The 1:1 circle below is already set to size 4: 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 414.88 mm · 0.586" inside · 46.8 mm round
Inside diameter14.88 mm
Band wall1.8 mm
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Full chart 19 rows

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Size 4 and the quarter sizes around it

9 rows
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US ring size 4 and quarter sizes within one size either side: inside diameter, difference in mm, circumference, UK and EU sizes
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14.07−0.81 mm44.2F½44
14.27−0.61 mm44.8G45
14.47−0.41 mm45.5G½45
14.68−0.20 mm46.1H46
14.88—46.8H½47
15.08+0.20 mm47.4I47
15.29+0.41 mm48.0I½48
15.49+0.61 mm48.7J49
15.69+0.81 mm49.3J½49

Ordering a size 4 in different band widths

4 rows
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What size to order for a US size 4 finger in narrow, 4–6 mm, 7 mm and wider, and comfort-fit bands
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414.88Bands under 4 mm usually fit true to size.
4¼–4½15.08–15.29A 4–6 mm band covers more skin and feels snugger: jewellers suggest a quarter to a half size up.
4½–515.29–15.69Wide and cigar bands grip the whole finger segment: half a size to a full size up.
3½–3¾14.47–14.68A domed comfort-fit inside slips over the knuckle more easily: often a quarter to a half size down.

Blank length for a size 4 band

6 rows
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Length of wire or sheet to cut for a US size 4 ring band (14.88 mm inside) in stock 1.0 to 2.5 mm thick, by π × (inside diameter + thickness)
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49.91.964"16.88
50.51.989"17.28
51.52.026"17.88
52.42.063"18.48
53.02.088"18.88
54.62.150"19.88

05 / Field guide

Size 4,
14.88 mm inside.

Everything about a US 4: 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 3½ and size 4½.

Who wears a size 4

A US 4 is a smaller women’s size, below the 6 to 8½ range most women wear, and a common pinky size for men. Jewellers’ order data puts the most common women’s size at 7 and men’s at 10, so a 4 is 3 sizes below the usual women’s size and 6 sizes 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 3½ (14.47 mm) and 0.41 mm narrower than a 4½ (15.29 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 4 by most of a size.

Size 4 in the UK, Europe and Japan

A 4 is 46.8 mm round. UK letters on the BS 6820 scale cover 0.625 mm each with half sizes, and H½ runs from 46.56 to 47.19 mm, so a 4 sits near the bottom of H½. If you are on the small side of a 4, a UK H may suit better.

ISO 8653 rounds to the nearest millimetre, so EU 47 covers 46.5 to 47.5 mm and a 4 lands 0.25 mm into that band. Swiss and Italian sizes subtract 40, giving 7. Japan 7 is 15.0 mm inside, 0.12 mm larger than a US 4, so Japanese 7 is the nearest match.

Quarter sizes either side

A 3¾ is 14.68 mm and a 4¼ is 15.08 mm, each about 0.2 mm from a 4: roughly the thickness of two sheets of paper on the diameter. If your ring falls between 3¾ and 4¼ on the 1:1 circle, order a 4 for a band under 4 mm.

For a 4–6 mm band, jewellers suggest 4¼ to 4½; for 7 mm and wider, 4½ to 5; for a comfort-fit inside, 3½ to 3¾. Smart-ring kits that include a size 4 sample: Oura Ring 4. Galaxy Ring and Ring AIR do not reach it.

Making a size 4 band

The blank length is the circumference of the middle of the band wall: π × (14.88 + thickness). Cut 51.5 mm of 1.5 mm stock or 53.0 mm of 2.0 mm stock, and the finished band has an outside diameter of 17.88 or 18.88 mm. Leave a little extra for filing the joint, and true the band on a mandrel at 4 after soldering.

Blank = π × (14.88 mm + t) · 1.5 mm → 51.5 mm · 2.0 mm → 53.0 mm

Questions

Answered plainly.

01What is a size 4 ring in mm?+

A US size 4 ring is 14.88 mm (0.586") across the inside, with an inside circumference of 46.8 mm (1.84").

02What is a US size 4 in UK and EU sizes?+

US 4 is UK H½ and EU (ISO 8653) 47. It is also Japan 7 and Swiss 7.

03How much bigger is a size 4½ than a size 4?+

A size 4½ is 0.41 mm wider inside (15.29 against 14.88 mm) and 1.28 mm longer round.

04How long a blank do I cut for a size 4 ring?+

51.5 mm for 1.5 mm thick stock and 53.0 mm for 2.0 mm, from π × (14.88 mm + thickness).

05Should I order a size 4 for a wide band?+

For a band 7 mm or wider, jewellers suggest 4½ to 5; for 4–6 mm, 4¼ to 4½. Under 4 mm, a 4 fits true to size.

Ring sizesUS · inside Ø mm

Carat sizes

Necklace lengths