Ring size 8.5 in mm, cm, UK and EU

Ring size 8½ in the US means a ring 18.5 mm wide inside and 58.3 mm round. The UK calls the same ring Q½, Europe 58, Japan 17 and India 18.

Ring size 8.5 in every system

Ring size 8.5 in mm, cm, UK and EU: every system
US and Canada	8½
UK, Ireland, Australia	Q½
Europe (EU)	58
Japan and China	17
India	18
Italy, Spain, Switzerland	18
Across the inside	18.5 mm · 1.85 cm · 0.730 in
Around the inside	58.3 mm · 5.8 cm · 2.30 in

One whole size bigger, US 9½, is just under 1 mm wider. All of these numbers are from the standard ring size conversion table.

Check a ring against ring size 8.5 on your screen

1Match a bank card

The card works like a ruler: nothing on it is read or saved, and a driving licence works too. Only its height counts, so the drawing may run off the edge of a phone. Hold the card flat on the screen, long side across, with its top edge on the drawing's top line. Then move the slider until the drawing's bottom line meets the card's bottom edge.

Optional. Only needed to lay a ring or strip on the screen; typed measurements work without it. Nothing on the card is read or saved.

2Measure

A ring I own My finger Print a sizer

Inside diameter of your ring mm

Lay the ring on the circle, or type the inside diameter if you measured it.

Length of your paper strip mm

Wrap a thin strip of paper around the base of your finger, mark where it overlaps, then measure to the mark.

The circle shows a 17.3 mm ring, drawn for a typical screen.

This size, drawn on your screen

US8½

UK Q½ · EU 58 · Japan 17 · India 18

18.5 mm (0.73 in) across the inside · 58.3 mm (2.30 in) around

For a wide band (over 4 mm), go up about half a size, to US 9.

See every size in the ring size chart · Convert a size you already know

Nearby sizes

Too tight or too loose? Try the size one row up or one row down.

Nearby sizes
US and Canada	UK and Australia	Europe (EU)	Inside diameter (mm)	Circumference (mm)
7½	O½	56	17.7	55.7
7¾	P	56	17.9	56.3
8	P½	57	18.1	57.0
8¼	Q	58	18.3	57.6
8½	Q½	58	18.5	58.3
8¾	R	59	18.8	58.9
9	R½	60	19.0	59.5
9¼	S	60	19.2	60.2
9½	S½	61	19.4	60.8

Common questions about ring size 8.5

How many millimetres is US ring size 8½?

It is 18.5 mm wide inside and 58.3 mm round the inside. In inches, the width is 0.73.

How many centimetres is US ring size 8½?

Round the inside it is 5.8 cm, and it is 1.85 cm wide.