Ring Sizing Guide
Part of: Promise rings
UK ring sizes run from A to Z by letter, US sizes by number and EU sizes by the inside circumference in millimetres. For example, a UK J is a US 4¾ and an EU 49; a UK L is a US 5¾ and an EU 51; a UK N is a US 6¾ and an EU 54. An EU size 50 is a UK K, or a US 5¼. The full chart below converts every size, with the circumference and diameter in millimetres so you can check a ring you already own.
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Ring size conversion chart
- A
- US
- ¼
- EU
- 38
- Circumference (mm)
- 37.8
- Diameter (mm)
- 12.0
- B
- US
- ¾
- EU
- 39
- Circumference (mm)
- 39.1
- Diameter (mm)
- 12.5
- C
- US
- 1¼
- EU
- 40
- Circumference (mm)
- 40.4
- Diameter (mm)
- 12.9
- D
- US
- 1¾
- EU
- 42
- Circumference (mm)
- 41.7
- Diameter (mm)
- 13.3
- E
- US
- 2¼
- EU
- 43
- Circumference (mm)
- 42.9
- Diameter (mm)
- 13.7
- F
- US
- 2¾
- EU
- 44
- Circumference (mm)
- 44.2
- Diameter (mm)
- 14.1
- G
- US
- 3¼
- EU
- 45
- Circumference (mm)
- 45.5
- Diameter (mm)
- 14.5
- H
- US
- 3¾
- EU
- 47
- Circumference (mm)
- 46.8
- Diameter (mm)
- 14.9
- I
- US
- 4¼
- EU
- 48
- Circumference (mm)
- 48.0
- Diameter (mm)
- 15.3
- J
- US
- 4¾
- EU
- 49
- Circumference (mm)
- 48.7
- Diameter (mm)
- 15.5
- K
- US
- 5¼
- EU
- 50
- Circumference (mm)
- 50.0
- Diameter (mm)
- 15.9
- L
- US
- 5¾
- EU
- 51
- Circumference (mm)
- 51.2
- Diameter (mm)
- 16.3
- M
- US
- 6¼
- EU
- 52
- Circumference (mm)
- 52.5
- Diameter (mm)
- 16.7
- N
- US
- 6¾
- EU
- 54
- Circumference (mm)
- 53.8
- Diameter (mm)
- 17.1
- O
- US
- 7¼
- EU
- 55
- Circumference (mm)
- 55.1
- Diameter (mm)
- 17.5
- P
- US
- 7¾
- EU
- 56
- Circumference (mm)
- 56.3
- Diameter (mm)
- 17.9
- Q
- US
- 8¼
- EU
- 58
- Circumference (mm)
- 57.6
- Diameter (mm)
- 18.3
- R
- US
- 8¾
- EU
- 59
- Circumference (mm)
- 58.9
- Diameter (mm)
- 18.8
- S
- US
- 9¼
- EU
- 60
- Circumference (mm)
- 60.2
- Diameter (mm)
- 19.2
- T
- US
- 9¾
- EU
- 61.5
- Circumference (mm)
- 61.4
- Diameter (mm)
- 19.6
- U
- US
- 10¼
- EU
- 63
- Circumference (mm)
- 62.7
- Diameter (mm)
- 20.0
- V
- US
- 10¾
- EU
- 64
- Circumference (mm)
- 64.0
- Diameter (mm)
- 20.4
- W
- US
- 11¼
- EU
- 65
- Circumference (mm)
- 65.3
- Diameter (mm)
- 20.8
- X
- US
- 11¾
- EU
- 67
- Circumference (mm)
- 66.6
- Diameter (mm)
- 21.2
- Y
- US
- 12¼
- EU
- 68
- Circumference (mm)
- 67.8
- Diameter (mm)
- 21.6
- Z
- US
- 12¾
- EU
- 69
- Circumference (mm)
- 68.5
- Diameter (mm)
- 21.8
UK sizes also come in half sizes (for example L½), which sit halfway between the letters on either side.
How to measure your ring size at home
- Measure a ring that fits. Lay it on a ruler and measure the inside diameter in millimetres, then find the nearest diameter in the chart.
- Measure your finger. Wrap a thin strip of paper or non-stretch string around the base of the finger, mark where it meets, and measure the length in millimetres. That is the circumference; find the nearest figure in the chart.
- Use a ring sizer. A set of sizing rings, or a plastic sizing strip, gives the most reliable result at home.
Tips for an accurate size
- Measure at the end of the day, when fingers are at their largest, and not when your hands are cold.
- Check the knuckle. The ring must pass over the knuckle; if your knuckle is large, choose the size that slides over it.
- Wide bands fit tighter. For a band wider than about 6 mm, go up half a size.
- Between two sizes, choose the larger.
Resizing antique rings
0 of 2 checked
1Many antique rings can be resized by
Many antique rings can be resized by a skilled jeweller, but some cannot: eternity rings set all the way round, rings with enamel, and some gem-set or engraved shanks.
2Resizing can also cut through or distort
Resizing can also cut through or distort the hallmark, which matters for value, so ask the jeweller to work away from the marks.
Have an antique or designer ring to sell? Send clear photographs of the ring, the inside of the band and any marks for a free, honest check.
Free, no obligation, returned at our cost if you decline.
What makes an antique ring valuable?
The maker and marks, the metal, the stones (type, size and quality), the period and design, the condition, and any original box or certificate. Size has little effect, because most rings can be resized. We never publish figures; every piece is different.
Free, no obligation, and returned at our cost if you decline.
Read our Google reviews (opens Google)
- Maker
- Metal
- Stones
- Period
- Condition
- Box
How selling works
- 1
Send photographs
of the ring, the inside of the band and any marks or box.
- 2
Free value inspection
We reply within one working day with an estimate, subject to inspection. If our offer differs, you can decline and we return it at our cost.
- 3
Paid the same day after inspection
by bank transfer or in cash, in Mayfair, at our Braintree office, by post or by free collection.
Questions people ask
What ring size is 50?
An EU size 50 is a UK K, or a US 5¼, with an inside circumference of about 50 mm.
What is ring size 50 in the UK?
UK K.
What is a UK L in US sizes?
A US 5¾, and an EU 51.
What is the average ring size for women in the UK?
Most women’s rings sold in the UK fall between J and N, with L and M among the most common.
How do I convert a UK ring size to US?
Use the chart: each UK letter is half a US size above the one before, and UK J is a US 4¾.
Can a ring be resized?
Most can, by a jeweller, though eternity rings, enamelled rings and some gem-set rings cannot be resized easily.
Related guides
Have a ring to sell?
Send a few photographs and we will tell you what it is and what it is worth, free.
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