Ring size guide

Every ring we list has its AU letter size and its inside diameter in millimetres, measured on a steel mandrel. Here’s how to find yours.

Measure a ring you already own

1. Choose a ring that fits the finger you’re buying for.
2. Lay it flat on a ruler and measure straight across the inside, edge to edge, in millimetres.
3. Find the closest diameter in the table. If you’re between two sizes, choose the larger.

Measure your finger

Wrap a strip of paper around the base of your finger, mark where it overlaps and measure the length in millimetres. That’s the circumference. Measure at the end of the day, when fingers are largest, and make sure the strip slides over your knuckle.

AU ring sizes

AU size	Inside diameter	Circumference
F	14.1 mm	44.3 mm
F½	14.3 mm	44.9 mm
G	14.5 mm	45.6 mm
G½	14.7 mm	46.2 mm
H	14.9 mm	46.8 mm
H½	15.1 mm	47.4 mm
I	15.3 mm	48.1 mm
I½	15.4 mm	48.4 mm
J	15.5 mm	48.7 mm
J½	15.7 mm	49.3 mm
K	15.9 mm	50.0 mm
K½	16.1 mm	50.6 mm
L	16.3 mm	51.2 mm
L½	16.5 mm	51.8 mm
M	16.7 mm	52.5 mm
M½	16.9 mm	53.1 mm
N	17.1 mm	53.7 mm
N½	17.3 mm	54.3 mm
O	17.5 mm	55.0 mm
O½	17.7 mm	55.6 mm
P	17.9 mm	56.2 mm
P½	18.1 mm	56.9 mm
Q	18.3 mm	57.5 mm
Q½	18.6 mm	58.4 mm
R	18.8 mm	59.1 mm
R½	19.0 mm	59.7 mm
S	19.2 mm	60.3 mm
S½	19.4 mm	60.9 mm
T	19.6 mm	61.6 mm
T½	19.8 mm	62.2 mm
U	20.0 mm	62.8 mm
U½	20.2 mm	63.5 mm
V	20.4 mm	64.1 mm
V½	20.6 mm	64.7 mm
W	20.8 mm	65.3 mm
W½	21.0 mm	66.0 mm
X	21.2 mm	66.6 mm
X½	21.4 mm	67.2 mm
Y	21.6 mm	67.9 mm
Y½	21.8 mm	68.5 mm
Z	22.0 mm	69.1 mm

Printable sizer

Print our ring sizer at 100% scale (not “fit to page”), check the 5 cm scale bar with a ruler, then cut it out and wrap it around your finger.

Can’t find your size? Tell us what you’re after and we’ll look out for it.