A ring size is a circumference in millimetres wearing a costume. Measure the millimetres and every country's answer falls out of one table.
The European ring system is refreshingly honest: the size is the inside circumference of the band in millimetres. A EU 52 ring measures 52 mm around the inside, and that is a US 6 and a UK L. Measure the millimetres and you have every system at once.
Method 1 — a strip of paper
Cut a strip of paper about 5 mm wide and 10 cm long. Paper, not string — string stretches and lies to you.
Wrap it around the base of the finger, snug but not tight, and mark where the strip overlaps itself.
Check it will pass over the knuckle before you unwrap it. If it will not, loosen until it just does.
Unwrap and measure to the mark with a ruler. That length in millimetres is the circumference.
Read it off the table below.
Method 2 — a ring that already fits
Measure the inside diameter of the ring across its widest point in millimetres, and multiply by 3.14. That gives you the circumference, which is the same number the first method produces. This is the method to use when the finger is not available — because, for instance, it belongs to someone who is not supposed to know you are measuring it.
Circumference → ring size
Women's — Ring by Finger circumference
mmFinger circumference
USUnited States
EUEurope
UKUnited Kingdom
JPJapan
KRKorea
CNChina
44
3
44
F
3
3
6
46
3.5
46
G
5
5
7
47
4
47
H
7
7
8
48
4.5
48
I
8
8
9
49
5
49
J
9
9
10
51
5.5
51
K
11
11
11
52
6
52
L
12
12
12
53
6.5
53
M
13
13
13
54
7
54
N
14
14
14
55.5
7.5
55.5
O
15
15
15
57
8
57
P
16
16
16
58
8.5
58
Q
17
17
17
59
9
59
R
18
18
18
60.5
9.5
60.5
S
19
19
19
62
10
62
T
20
20
20
63
10.5
63
U
21
21
21
64.5
11
64.5
V
22
22
22
Men's — Ring by Finger circumference
mmFinger circumference
USUnited States
EUEurope
UKUnited Kingdom
JPJapan
KRKorea
CNChina
44
3
44
F
3
3
6
46
3.5
46
G
5
5
7
47
4
47
H
7
7
8
48
4.5
48
I
8
8
9
49
5
49
J
9
9
10
51
5.5
51
K
11
11
11
52
6
52
L
12
12
12
53
6.5
53
M
13
13
13
54
7
54
N
14
14
14
55.5
7.5
55.5
O
15
15
15
57
8
57
P
16
16
16
58
8.5
58
Q
17
17
17
59
9
59
R
18
18
18
60.5
9.5
60.5
S
19
19
19
62
10
62
T
20
20
20
63
10.5
63
U
21
21
21
64.5
11
64.5
V
22
22
22
Getting it right the first time
Measure warm, in the evening. Cold fingers are measurably thinner, and fingers swell slightly through the day. Measure at the extreme you will actually wear it at.
The knuckle decides. If the knuckle is much wider than the base of the finger, size for the knuckle — a ring you cannot get on is not a small problem — and expect it to spin a little.
Wide bands run tight. A band more than about 6 mm wide usually needs a half size up on the same finger.
Measure the exact finger. Left and right hands differ, and so do the fingers on one hand.
Buying a surprise? Borrow a ring they already wear on that finger and use method 2. Or ask someone who can ask without giving it away.
Common questions
What is a US ring size 6 in UK and EU?
UK L and EU 52 — the EU number being the inside circumference in millimetres, 52 mm.
Can I measure a ring size with string?
Not reliably — string stretches under tension and the result comes out a size too small. Use a strip of paper, which does not.
When is the best time of day to measure?
The evening, with warm hands. Fingers are at their smallest when cold and first thing in the morning, which is exactly when you should not be sizing a ring.
How do I find someone's ring size without asking?
Take a ring they already wear on the right finger and measure its inside diameter in millimetres, then multiply by 3.14. Failing that, ask a friend or family member to find out — or send them a size request they can fill in without you ever seeing the question.
The charts behind this
More guides
MeSize
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