How do I measure my ring size at home?

Wrap a strip of paper around your finger, mark where it overlaps, measure the length in mm. That is your finger circumference. Divide by π (3.14159) to get the diameter, then match to a ring size chart.

What is ring size 7 in mm?

US ring size 7 = approximately 17.35 mm diameter (inner circumference of about 54.5 mm).

How do I convert US ring size to UK?

US ring sizes use numbers while UK uses letters. US size 6 ≈ UK size L½, US size 7 ≈ UK size N½, US size 8 ≈ UK size P½.

What is the most common ring size for women?

The most common ring size for women in the US is size 6 (16.51 mm diameter). For men, size 9-10 (19-20 mm) is most common.

How to Measure Ring Size at Home — US, UK, EU Guide

Buying a ring online or from abroad means you need to know your ring size in the right system. Different countries use completely different sizing systems, but this guide makes conversion simple.

How to Measure Your Ring Size at Home

Method 1: String or Paper Strip

Cut a thin strip of paper or use a piece of string (about 10cm long)
Wrap it around the base of your finger snugly (not too tight)
Mark where the strip overlaps with a pen
Measure the length from the end to the mark in millimetres
This is your finger circumference — use the table below to find your size

Method 2: Measure an Existing Ring

Place a ring you already own on a ruler. Measure the internal diameter in millimetres. Use the table below to find your size.

Ring Size Conversion Chart

Diameter (mm)	Circumference (mm)	US Size	UK Size	EU Size
15.7 mm	49.3 mm	5	J½	49
16.5 mm	51.9 mm	6	L½	52
17.3 mm	54.4 mm	7	N½	54
18.2 mm	57.0 mm	8	P½	57
19.0 mm	59.5 mm	9	R½	60
19.8 mm	62.1 mm	10	T½	62

Tips for Accurate Measurement

Measure in the evening — fingers are slightly larger later in the day and when warm
Measure the correct finger — fingers on your dominant hand are typically slightly larger
Consider the knuckle — if your knuckle is wider than your finger base, size up slightly
Measure 2–3 times — take the average for accuracy

Average Ring Sizes

Average women's ring size: US 6–7 (UK M–O, EU 52–54). Average men's ring size: US 9–10 (UK R–T, EU 60–63). These are averages only — always measure before ordering.