International Ring Size Comparison Chart

5 min read•June 1, 2025•Reviewed: June 1, 2026

✓Reviewed by Apex Conversion Editorial Team · Last reviewed June 1, 2026

Ring size numbering differs radically by country. This page provides a complete reference table covering US, EU (circumference in mm), UK (letters), Japanese (numbers), and inner diameter in millimeters — all in one place for quick lookup.

The most universal reference point is inner diameter in millimeters. If you know the diameter of a ring that fits you, you can find your size in every system from this table.

Complete Ring Size Comparison Chart

US    EU    UK    JP    Diam (mm)  Circ (mm)
────  ──    ───   ──    ─────────  ─────────
 3    44    F     3     13.9        43.7
 3.5  46    G     4     14.4        45.2
 4    47    H½    7     15.0        47.1
 4.5  48    I     8     15.3        48.0
 5    49    J½    9     15.7        49.3
 5.5  51    K½   10     16.1        50.6
 6    52    L½   12     16.5        51.8
 6.5  53    M    13     16.9        53.1
 7    54    N½   13     17.3        54.4
 7.5  56    O½   15     17.7        55.6
 8    57    P½   15     18.2        57.2
 8.5  58    Q    16     18.6        58.4
 9    59    R½   18     18.9        59.4
 9.5  61    S    19     19.4        60.9
10    62    T½   20     19.8        62.2
10.5  63    U    21     20.2        63.5
11    64    V½   22     20.6        64.7
11.5  66    W    23     21.0        66.0
12    67    X½   24     21.4        67.2
13    70    Z½   27     22.2        69.7

Understanding the Chart

The diameter column is the inner diameter of the ring in millimeters — the most precise physical measurement. The circumference is the inner circumference (diameter × π). EU sizes equal the inner circumference in mm. This means EU 54 = 54 mm circumference = 17.2 mm diameter.

UK sizes use letters where each step is approximately 0.4 mm of diameter. The half-size notation (N½, P½) appears frequently because the UK alphabet advances in steps that do not align with US half-size steps.

Common Ring Sizes by Demographic

Women's ring sizes in the US most commonly fall between size 5 and size 8, with size 6 and 7 being the most common. Men's ring sizes most commonly fall between size 8 and size 12, with size 10 being the most common.

These are averages — finger size varies greatly based on height, weight, and genetics. Do not assume a size based on demographics; always measure the specific person.

Quick Tips

✓
The most commonly gifted engagement ring sizes are US 6 (EU 52, UK L½) for women and US 10 (EU 62, UK T½) for men.
✓
If ordering a surprise ring, go half a size large — resizing down is easier than up for most ring styles.
✓
Japanese ring sizes run similarly to US sizes but are numbered differently. JP 13 ≈ US 7.
✓
For fashion rings and large cocktail rings, consider going half a size up — they tend to be heavier and fit tighter.

Frequently Asked Questions

What is the most common women's ring size?

In the US, the most common women's ring finger size is approximately US 6–7 (EU 52–54, UK L½–N½). This varies by region and body type.

What is the most common men's ring size?

In the US, the most common men's ring finger size is approximately US 9–11 (EU 59–64, UK R½–V½).

Why does the chart show half-size jumps in UK letters?

UK ring sizes advance in alphabet letters where each letter = approximately 0.4 mm. US half sizes = approximately 0.4 mm. They do not align perfectly, so some US half sizes fall between UK whole letters.