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 Ring Size Conversion Chart


UK to US size conversion chart · UK to EU conversion chart 

Order Our Handy Ring Sizer Tool 

The cost of the ring size tool will be refunded after you place any order.

Place an Order with UK or US sizing

Did you know that you can order a ring by telling us the UK or US finger size? We are happy to work with either system. Alternatively, order our UK ring sizer to estimate the correct finger size needed for your ring. We send each ring sizer out same day. In addition, the ring sizer will be refunded against any order placed once you know your finger size. 

Find Your Ring Size

Determine your ring size using any of our visual or ring sizer tool available from Serendipity Diamonds. For US to UK sizes, use our ring size conversion table below. With exceptional customer service, our small and friendly team remain on hand to help with any questions. 

Refer to our international ring size conversion chart in the lower section of this page for an accurate conversion from UK to US or EU ring sizes. We have included the internal diameter in mm. for most ring sizes. Our ring size converter works for both Wedding Rings and Engagement Rings.  

Arranging Your Ring Sizer

You will notice that all of the rings on our website feature a button to order a UK ring sizer which we send out by UK or International post immediately for you followed by our confirmation email. This handy Multisizer system works as a strap around the finger and is re-usable. Order yours via the website button above. 

UK ring sizes to US sizes

Owing to our website showing UK finger sizes, please feel free to look at the size stick which shows UK equivalents to US sizes. We have included this due to the variation of opinion between many conversion charts. If there is no clear equivalent size – contact us – we will be happy to work to the US finger size when we create your ring.  

Free Advice - Call or Email

Please scroll down for a full size conversion chart.

Please keep in mind that some ring designs cannot be re-sized for a variety of reasons. Full eternity rings are the most obvious example of rings that cannot be adjusted by size. Engagement rings with tension style settings are unsuitable for significant size alterations. Claw settings are the most popular style purchased with any uncertainty about finger size. Following size adjustments, claws or prongs can be re-tensioned around the Diamond to ensure security for the stone. If you are uncertain about finger size, please feel free to contact us at any time for additional guidance. 

Guidance on Typical Finger Sizes

To give you a better idea of how different sizes compare, the following information assigns groups of sizes to small, medium and large finger sizes. If you are unable to take a specific size reading, this information might help you select a size that will be close to the correct finger size. Your ring will likely need less of an adjustment following purchase. We can help with any size adjustments in the future, after purchase. 

  • Sizes G - I Very small sizes
  • Sizes J - K Typical for smaller hands
  • Sizes L - N Mid / average sizes
  • Sizes O - P Slightly larger sizes
  • Sizes Q - T Larger finger sizes
  • Sizes T - Z Very large sizes

Ring Size Charts

The ring size chart below gives some guidance on conversion. Please remember that we can work to in-between finger sizes. Our website allows a full or half size to be chosen. By contacting us before or after placing your order, we can apply further increments. For example you might need size L and a quarter (quarter of a size larger than L) In this instance a size L and a quarter is equivalent to a US size 6. This is no problem to apply if you contact us before or after placing your order. 

Help I have no idea!

If you really have no idea on your partner's finger size, please look at the guidance notes above (4th Paragraph) and we can choose a suitable 'guesstimate' to make the ring. Since we provide a free ring size adjustment for most ring styles, making an alteration will not be a problem. Please see our terms and conditions as to which styles are not included in the free resize.

Ring Size Guide - International Ring Size Chart

American British European Inside Diameter (mm)
A 12.065
38 12.096
1 12.344
39 12.344
B 12.459
40 12.733
C 12.852
41 13.051
2 13.157
D 13.246
42 13.369
E 13.640
43 13.687
3 13.970
44 14.006
F 14.034
45 14.324
G 14.427
46 14.642
4 14.783
H 14.821
47 14.961
I 15.215
48 15.279
5 49 15.597
J 15.608
50 15.916
K 16.002
51 16.234
6 L 16.396
52 16.552
M 16.789
53 16.871
N 17.183
54 17.189
7 17.221
55 17.507
O 17.577
56 17.826
P 17.971
8 18.034
57 18.144
Q 18.364
58 18.462
R 18.758
59 18.780
9 18.872
60 19.098
S 19.152
60 19.098
61 19.416
T 19.545
10 19.761
U 19.939
63 20.054
10½ 20.168
V 20.333
64 20.372
11 20.599
65 20.690
W 20.726
11½ 66 21.008
X 21.120
67 21.326
12 21.412
Y 21.514
68 21.645
12½ 21.819
Z 21.908
69 21.963
13 22.252