Ring Size Guide

Enter your finger circumference in mm:

What Ring Size am I?

If you're wondering where to find your ring size then you've come to the right place! Getting an accurate ring size is an important step before investing in a precious ring. Rings which are too small can cause swelling, discomfort and can lead to circulation issues. Rings which are too large are likely to slip - and may even fall off your finger altogether. So whether you're looking to find the ring size of a loved one to purchase an engagement ring (congrats!), or just want to treat yourself but aren't sure about your size, here's our helpful guide.



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If you simply want to know what your own ring size is, we've made the following table which compares UK, USA and European ring sizes alongside diameter (one side to the other) and circumference (distance around the edge) measurements in mm and inches.

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You should measure your ring finger at the end of the day before you go to bed (but before you brush your teeth, as the cold water may make your finger slightly smaller - we're not kidding!). We recommend you measure your ring finger 3 or 4 times to get an accurate size.

We don't recommend that you use paper or string to measure your ring finger, as these materials are often slightly elastic or can stretch out of shape. Instead, why not order one of our ring sizers which will arrive with you in the post in a few days?

Thankfully yes. Making things a little simpler, whichever ring size scale you use, the numbers and letters mean the same thing for men and women. Of course, a men's ring will likely be manufactured in larger sizes than a women's ring.

Yes, we sometimes struggle to remember our school maths lessons too, so here's a quick refresher: The diameter is the distance across the ring from one side to the other. in the table below we deal with the inside diameter: inner-edge to inner-edge. The circumference is the distance all the way around the inside of the ring - think 'circ-le' = 'circ-umerference'.

Ring sizes in different countries

Just to keep you on your toes, ring sizes can be different in different countries. The UK, USA and Canada, France, Germany, Japan and Switzerland all have a slightly different ring size scale - you can see how they vary, and convert one type to another in the ring size table below.

a quick ring-size geography lesson

Ring sizes are laughably inconsistent across the world - Brazil have their own thing going on; most of Europe has its own scale - apart from Germany who decided that wasn't good enough for them (Argentina agreed - they use the German ring size scale too).

UK ring sizes

The UK uses a system of letters, plus a fraction - e.g. a, a 1/2, b etc. The closer the letter to the end of the alphabet, the larger the ring size. Once you get to 'z', the UK ring sizes start adding on extra sizes with a '+' symbol followed by a number - e.g. z+3, z+3.5 etc. Note that this system is also used in Australia, New Zealand, Ireland and South Africa

US & Canadian ring sizes

You might also come across US ring sizes, which are also used in Canada. These are made up of numbers only, starting at '0000', '000', '00', '0', '1/2', '3/4' '1'; going up to '13.5'. The US system of ring sizes goes smaller than the UK, covering sizes all the way down to 31.33mm in circumference. However, the UK system covers larger sizes at the opposite end of the scale.

Asian ring sizes

Marked as 'Japanese' in our table (as this is where this scale originated), the Asian ring size is used across the entire continent, including India, China and the Middle East (though not Hong Kong, confusingly!). This scale is also used in some South American countries such as Peru and Bolivia. It's the simplest to figure out as it's literally just a case of counting up 1, 2, 3 - there's no fractions or letters to deal with! However, this means it covers fewer sizes than some of the other scales.

Ring Size Table

The table lets you convert your ring size from one country's sizing system to another, as well as from the size in mm or inches into a ring size. On jewellerybox.co.uk, we use the UK ring size (since we're from the UK!).

Inside Diameter Inside Circumference International Ring Sizes
MM Inches MM Inches UK USA & Canada French German Japanese Swiss
9.91 0.390 31.13 1.22 - 0000 - - - -
10.72 0.442 33.68 1.39 - 00 - - - -
11.53 0.454 36.22 1.43 - 0 - - - -
11.95 0.474 37.54 1.49 A 1/2 - - - -
12.18 0.482 38.26 1.51 A 1/2 3/4 - - - -
12.37 0.487 38.86 1.53 B 1 - - 1 -
12.60 0.496 39.58 1.56 B 1/2 1 1/4 - - - -
12.78 0.503 40.15 1.58 C 1 1/2 - - - -
13.00 0.512 40.84 1.61 C 1/2 1 3/4 - - - -
13.21 0.520 41.50 1.63 D 2 41 1/2 13 1/2 2 1 1/2
13.41 0.528 42.13 1.66 D 1/2 2 1/4 - - - -
13.61 0.536 42.76 1.68 E 2 1/2 42 3/4 13 3/4 3 2 3/4
13.83 0.544 43.45 1.71 E 1/2 2 3/4 - - - -
14.05 0.553 44.14 1.74 F 3 44 14 4 4
14.15 0.557 44.45 1.75 F 1/2 3 1/8 - - - -
14.25 0.561 44.77 1.76 F 3/4 3 1/4 - - - -
14.36 0.565 45.11 1.77 G 3 3/8 45 1/4 - 5 5 1/4
14.45 0.569 45.40 1.79 G 1/4 3 1/2 - 14 1/2 - -
14.56 0.573 45.74 1.80 G 1/2 3 5/8 - - 6 -
14.65 0.577 46.02 1.81 H 3 3/4 46 1/2 - - 6 1/2
14.86 0.585 46.68 1.84 H 1/2 4 - 15 7 -
15.04 0.592 47.25 1.86 I 4 1/4 47 3/4 - - 7 3/4
15.27 0.601 47.97 1.89 I 1/2 4 1/2 - 15 1/4 8 -
15.40 0.606 48.38 1.90 J 4 5/8 49 15 1/2 - 9
15.53 0.611 48.79 1.92 J 1/4 4 3/4 - - - -
15.70 0.618 49.32 1.94 J 1/2 5 - 15 3/4 9 -
15.80 0.622 49.64 1.95 K 5 1/8 50 - - 10
15.90 0.626 49.95 1.97 K 1/4 5 1/4 - - - -
16.00 0.630 50.27 1.98 K 1/2 5 3/8 - - 10 -
16.10 0.634 50.58 1.99 L 5 1/2 51 3/4 16 - 11 3/4
16.30 0.642 51.21 2.02 L 1/4 5 3/4 - - - -
16.41 0.646 51.55 2.03 L 1/2 5 7/8 - - - -
16.51 0.650 51.87 2.04 M 6 52 3/4 16 1/2 12 12 3/4
16.71 0.658 52.50 2.07 M 1/2 6 1/4 - - - -
16.92 0.666 53.16 2.09 N 6 1/2 54 17 13 14
17.13 0.674 53.82 2.12 N 1/2 6 3/4 - - - -
17.35 0.683 54.51 2.15 O 7 55 1/4 17 1/4 14 15 1/4
17.45 0.687 54.82 2.16 O 1/2 7 1/4 - - - -
17.75 0.699 55.76 2.20 P 7 1/2 56 1/2 17 3/4 15 16 1/2
17.97 0.707 56.45 2.22 P 1/2 7 3/4 - - - -
18.19 0.716 57.15 2.25 Q 8 57 3/4 18 16 17 3/4
18.35 0.722 57.65 2.27 Q 1/2 8 1/4 - - - -
18.53 0.729 58.21 2.29 Q 3/4 8 1/2 - 18 1/2 17 -
18.61 0.733 58.47 2.30 R 8 5/8 59 - - 19
18.69 0.736 58.72 2.31 R 1/4 8 3/4 - - - -
18.80 0.740 59.06 2.32 R 1/2 8 7/8 - - - -
18.89 0.748 59.34 2.35 R 3/4 9 - 19 18 -
19.10 0.752 60.00 2.36 S 9 1/8 60 1/4 - - 20 1/4
19.22 0.757 60.38 2.38 S 1/4 9 1/4 - - - -
19.31 0.760 60.66 2.39 S 1/2 9 3/8 - - - -
19.41 0.764 60.98 2.40 S 3/4 9 1/2 - 19 1/2 19 -
19.51 0.768 61.29 2.41 T 9 5/8 61 1/2 - - 21 1/2
19.62 0.772 61.64 2.43 T 1/4 9 3/4 - - - -
19.84 0.781 62.33 2.45 T 1/2 10 - 20 20 -
20.02 0.788 62.89 2.48 U 10 1/4 62 3/4 - 21 22 3/4
20.20 0.797 63.46 2.50 U 1/2 10 1/2 - 20 1/4 22 -
20.32 0.800 63.84 2.51 V 10 5/8 63 - - 23 3/4
20.44 0.805 64.21 2.53 V 1/4 10 3/4 - - - -
20.68 0.814 64.97 2.56 V 1/2 11 - 20 3/4 23 -
20.76 0.817 65.22 2.57 W 11 1/8 65 - - 25
20.85 0.821 65.50 2.58 W 1/4 11 1/4 - - - -
20.94 0.824 65.78 2.59 W 1/2 11 3/8 - - - -
21.08 0.830 66.22 2.61 W 3/4 11 1/2 - 21 24 -
21.18 0.834 66.54 2.62 X 11 5/8 66 1/4 - - 26 1/4
21.24 0.836 66.73 2.63 X 1/4 11 3/4 - - - -
21.30 0.839 66.92 2.64 X 1/2 11 7/8 - - - -
21.49 0.846 67.51 2.66 Y 12 67 1/2 21 1/4 25 27 1/2
21.69 0.854 68.14 2.68 Y 1/2 12 1/4 - - - -
21.89 0.862 68.77 2.71 Z 12 1/2 68 3/4 21 3/4 26 28 3/4
22.10 0.870 69.43 2.73 Z +1/2 12 3/4 - - - -
22.33 0.879 70.15 2.76 Z+1 13 - 22 27 -
22.60 0.890 71.00 2.80 Z+1.5 13.5 - - - -
22.69 0.893 71.28 2.81 Z+2 - - - - -
22.92 0.902 72.00 2.83 Z+2.5 - - - - -
23.06 0.908 72.45 2.85 Z+3 - - - - -
23.24 0.915 73.01 2.87 Z+3.5 - - - - -
23.47 0.924 73.73 2.90 Z+4 - - - - -
23.55 0.927 73.98 2.91 Z+4.5 - - - - -
23.87 0.940 74.99 2.95 Z+5 - - - - -
24.27 0.956 76.25 3.00 Z+6 - - - - -
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