1. Take a ring that fits the finger you have in mind.
2. Lay a ruler across the inside of it and measure straight across the middle, in millimetres.
3. Find that figure in the Inside diameter column below.
Method two
Measure the finger itself
1. Wrap a strip of paper or a thread around the base of the finger — snug, not tight.
2. Mark where it meets, then lay it flat and measure the length in millimetres.
3. Find that figure in the Circumference column below.
Worth knowing
Measure in the evening. Fingers swell through the day, and a ring that fits at 8 in the morning can be tight by night.
Not when your hands are cold. Cold fingers measure smaller than they really are.
A wide band needs a size more. Anything above about 6 mm across sits tighter than a thin one of the same size.
Check the knuckle. The ring has to pass it. If your knuckle is much larger than the base of the finger, take the size in between.
Indian size
Inside diameter
Circumference
US
UK
1
12.04 mm
37.8 mm
0¾
A
2
12.45 mm
39.1 mm
1¼
B
3
12.85 mm
40.4 mm
1¾
C
4
13.26 mm
41.7 mm
2¼
D
5
13.67 mm
42.9 mm
2¾
E
6
14.07 mm
44.2 mm
3¼
F
7
14.48 mm
45.5 mm
3¾
G
8
14.88 mm
46.8 mm
4
H
9
15.29 mm
48.0 mm
4½
I
10
15.70 mm
49.3 mm
5
J
11
16.10 mm
50.6 mm
5½
K
12
16.51 mm
51.9 mm
6
L
13
16.92 mm
53.1 mm
6½
M
14
17.32 mm
54.4 mm
7
N
15
17.73 mm
55.7 mm
7½
O
16
18.14 mm
57.0 mm
8
P
17
18.54 mm
58.3 mm
8½
Q
18
18.95 mm
59.5 mm
9
R
19
19.35 mm
60.8 mm
9½
S
20
19.76 mm
62.1 mm
10
T
21
20.17 mm
63.4 mm
10½
U
22
20.57 mm
64.6 mm
11
V
23
20.98 mm
65.9 mm
11½
W
24
21.39 mm
67.2 mm
12
X
25
21.79 mm
68.5 mm
12½
Y
26
22.20 mm
69.7 mm
13
Z
27
22.61 mm
71.0 mm
13½
Z+1
28
23.01 mm
72.3 mm
14
Z+2
29
23.42 mm
73.6 mm
14½
Z+3
30
23.83 mm
74.8 mm
15
Z+4
Still not certain?
Send us a photograph of your ruler against the ring and we will read the size for you. It takes a minute, and it is far quicker than sending a piece back.