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 Ring Size Chart UK to US Conversion

Ring Size Chart UK to US and European Measurements 

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 the same day. In addition, the ring sizer will be refunded against any order placed once you know your finger size. Use our handy rings guide to learn more about finger sizes and how to size your finger correctly.  

How does the ring size tool work

The ring sizer gives the UK finger size reading when wrapped around the finger. Find out your ring size at home. This system replaces DIY methods of getting your finger measured by using a piece of string. Measure your ring finger size with ease. Similar to a cable tie, one end inserts through a gap and tightens around the finger. Don't worry, the sizer will come off. 

Don't tighten the sizer too much, otherwise, the strap will open and give a false reading. To note, we apply a small refundable charge. Use the link above to order your UK ring size tool. The tool is reusable and easy easily recycled or passed to friends and family afterwards. A family member will likely have use for this at some point in the near future.   

Once you have the perfect ring size, talk to us and we will help you with the next stage, finding the perfect ring. 

Find Your Correct Ring Size - Get the Perfect Fit - Measure your ring finger at home

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. With our expert help, we aim to ensure your ring has the perfect fit. 

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, average ring size 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. We gladly offer help with any ring size conversion needed. 

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. Please note that some ring size conversion charts vary by subtle amounts. 

Ring Size Guide - International Ring Size Chart

The following chart provides every permutation to translate the correct finger size. This is a ring size chart UK to US. It is also a chart for US to UK. Choose your local size and then look up the inside diameter. Use the diameter measurement to calculate circumference using easy-to-use formulae. 

Circumference calculators feature online for anyone looking to work out this measurement. Use our chart to find the correct local size required. 

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

How to find out ring size from Circumference 

If you measure the circumference of a ring and need to find out the diameter and ring size, this can be done with a simple calculator. As part of our work, we use an online circumference to diameter calculator to firstly find out diameter. Using this system, convert circumference to diameter. Once you have your diameter, this can be checked against the ring size conversion chart above. 

Is there such a thing as a downloadable ring chart?

Some websites provide a downloadable ring showing finger sizes. Charts provide ring outlines onto which you can place an existing ring to estimate size. For example, we found the following downloadable ring chart online after a few simple searches. With the Multisizer tool both help you to measure your ring size in both UK and US size systems. 

Sizers for Men's rings 

In addition to women's ring sizers, we provide special blanks suitable for estimating the size of mens rings. Firstly, visit our dedicated product page order your Multisizer. Next, try on the Multisizer to estimate your size, pushing the tool to the base of the finger. Next, contact us with this size. We then send out three of the closest half sizes to double-check finger size. 

Order your men's ring size set here