Ring size 8 in mm, cm, UK and EU

Ring size 8 in the US means a ring 18.1 mm wide inside and 57.0 mm round. The UK calls the same ring P½, Europe 57, Japan 16 and India 17.

Ring size 8 in every system

Ring size 8 in mm, cm, UK and EU: every system
US and Canada	8
UK, Ireland, Australia	P½
Europe (EU)	57
Japan and China	16
India	17
Italy, Spain, Switzerland	17
Across the inside	18.1 mm · 1.81 cm · 0.714 in
Around the inside	57.0 mm · 5.7 cm · 2.24 in

One whole size bigger, US 9, 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 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

US8

UK P½ · EU 57 · Japan 16 · India 17

18.1 mm (0.71 in) across the inside · 57.0 mm (2.24 in) around

For a wide band (over 4 mm), go up about half a size, to US 8½.

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)
7	N½	54	17.3	54.4
7¼	O	55	17.5	55.1
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

Common questions about ring size 8

How many millimetres is US ring size 8?

It is 18.1 mm wide inside and 57.0 mm round the inside. In inches, the width is 0.71.

How many centimetres is US ring size 8?

Round the inside it is 5.7 cm, and it is 1.81 cm wide.