Ring Size Guide

If you already have your accurate finger measurement or already know your ring size but just need to convert it to another country’s size, use our ring size conversion chart table in MM or Inches for different countries:

SImply Bo ring size chart guide in mm an inches for usa canda and uk

Inside Diameter MM	Inside Diameter Inches	USA & Canada Ring Size	UK, Ireland, Australia & New Zealand Ring Size
15 mm	0.59	4	H
15.3 mm	0.60	4.5	I
15.6 mm	0.62	5	J
16.2 mm	0.63	5.5	K
16.5 mm	0.65	6	L
16.9 mm	0.67	6.5	M
17.3 mm	0.68	7	N
17.8 mm	0.70	7.5	O
18.2 mm	0.71	8	P
18.5 mm	0.73	8.5	Q
19.0 mm	0.75	9	R
19.4 mm	0.76	9.5	S
19.9 mm	0.78	10	T
20.4 mm	0.79	10.5	U
20.6 mm	0.81	11	V
21.0 mm	0.83	11.5	W
21.6 mm	0.84	12	X
22.0 mm	0.86	12.5	Y
22.3 mm	0.87	13	Z
22.9 mm	0.89	13.5	Z+2
23.2 mm	0.91	14	Z+3
23.6 mm	0.92	14.5	Z+4
24.0 mm	0.94	15	Z+5

Don't know your ring size? Here are a few options for finding out which size to choose:

Option 1

Tie a thread around the finger you want to measure. Don’t tie it too tight. Then measure the length of the thread in mm. The length of the thread corresponds to your size. Round off according to the table.

Option 2

Use a ring that fits and measure its inner measure using a measuring tape or a ring mandrel. Round off according to the table.

Tip: When measuring your finger, your measurements need to be a 100% accurate as even a fraction of a millimeter can make a difference