AU / UK Ring Size
N
Your Australian size = Your UK size
Australian and UK ring sizes use the exact same letter system — no conversion needed
Look up any AU/UK ring size to get the inner diameter (mm), finger circumference (mm), and equivalent US and EU sizes — all in one free tool for 2026.
Professional ring size reference for jewellers, online shoppers, and gift buyers across Australia, the UK, and worldwide
Australian and UK ring sizes use exactly the same alphabetical letter system — from approximately size F through to Z+1½. Your Australian ring size IS your UK ring size with no offset, no formula, and no conversion required. If your AU ring size is N, your UK ring size is also N. Both countries adopted the same British letter-based sizing standard, making cross-country ring shopping completely straightforward with zero ambiguity.
Use the calculator below to look up any AU/UK letter size and instantly see the exact inner ring diameter in mm, finger circumference in mm, and equivalent sizes in the US number system and European ISO system. The second tab lets you enter your measured finger circumference in millimetres to find your closest matching letter size — perfect for measuring at home before ordering a ring online from an Australian or UK jeweller.
Essential for buying rings online from UK or Australian jewellers, converting AU/UK sizes to US numbers for American brands, interpreting EU sizes from European retailers, checking a partner's ring size before buying a surprise gift, comparing ring sizing across international jewellery websites, understanding vintage ring labels, and confirming correct sizing for custom-made engagement rings and wedding bands ordered in 2026.
Look up any AU/UK size — or find your size by entering finger circumference in mm
Ring sizing in Australia and the United Kingdom follows an identical alphabetical letter system. Both countries adopted the British ring sizing standard, where sizes progress through the alphabet with half-size increments available (e.g., G, G½, H, H½). The system is used not just by Australia and the UK but also by Ireland, New Zealand, and South Africa — making it one of the most widely used ring sizing standards in the Commonwealth world. Each half-size increment represents an increase of approximately 0.75 mm in the ring's inner circumference.
The key practical implication is simple: there is no conversion needed between AU and UK ring sizes. A UK jeweller and an Australian jeweller both call a ring with an inner circumference of approximately 53.16 mm by the same name — size N. The confusion most people face is not AU vs UK (which are the same) but AU/UK vs the US numeric system or the European ISO system — both of which use entirely different numbering conventions to describe the same physical ring sizes.
Example: AU/UK size N = 16.92 mm diameter = 53.16 mm circumference = US 6½ = EU 53
Size N = ⌀ 16.92 mm = 53.16 mm circumference | Typical AU/UK women's sizes: M–P | Typical AU/UK men's sizes: R–T
You can find your AU/UK ring size accurately at home with just a strip of paper, a pen, and a ruler. Follow these five steps for a reliable result before ordering online:
Best time to measure: late afternoon, when fingers are at their largest (they shrink in the morning cold and in air conditioning). If you have large knuckles: measure both the knuckle and the base, then choose a size between the two. Wide bands: go up half a size — bands wider than 6 mm fit more tightly than narrow bands of the same size. Dominant hand: your dominant hand's fingers are typically slightly larger, so measure the specific finger on the specific hand you'll wear the ring on.
Complete reference for all common AU/UK ring sizes with exact inner diameter, circumference, US number size, and EU/ISO equivalent. The table covers sizes G through Z+1½ — the full commercial range stocked by Australian and UK jewellers. Orange rows indicate typical women's sizes; blue rows indicate typical men's sizes.
| AU / UK Size | Inner Diameter (mm) | Inner Circumference (mm) | US / Canada | EU / ISO | Notes |
|---|---|---|---|---|---|
| G | 14.36 | 45.11 | 3⅜ | 45 | Small |
| G 1/2 | 14.56 | 45.74 | 3⅝ | 46 | Small |
| H | 14.65 | 46.02 | 3¾ | 46 | Small |
| H 1/2 | 14.86 | 46.68 | 4 | 47 | Small |
| I | 15.04 | 47.25 | 4¼ | 47 | Small |
| I 1/2 | 15.27 | 47.97 | 4½ | 48 | Small |
| J | 15.40 | 48.38 | 4⅝ | 48 | Small women's |
| J 1/2 | 15.70 | 49.32 | 5 | 49 | Small women's |
| K | 15.80 | 49.64 | 5⅛ | 50 | Small women's |
| K 1/2 | 16.00 | 50.27 | 5⅜ | 50 | Small women's |
| L | 16.10 | 50.58 | 5½ | 51 | Women's |
| L 1/2 | 16.41 | 51.55 | 5⅞ | 52 | Women's |
| M | 16.51 | 51.87 | 6 | 52 | Avg women's (AU/UK) |
| M 1/2 | 16.71 | 52.50 | 6¼ | 53 | Avg women's |
| N | 16.92 | 53.16 | 6½ | 53 | Avg women's (AU/UK) |
| N 1/2 | 17.13 | 53.82 | 6¾ | 54 | Avg women's |
| O | 17.35 | 54.51 | 7 | 55 | Avg women's |
| O 1/2 | 17.45 | 54.82 | 7¼ | 55 | Avg women's |
| P | 17.75 | 55.76 | 7½ | 56 | Avg women's (AU/UK) |
| P 1/2 | 17.97 | 56.45 | 7¾ | 56 | Women's / small men's |
| Q | 18.19 | 57.15 | 8 | 57 | Women's / small men's |
| Q 1/2 | 18.35 | 57.65 | 8¼ | 58 | Small men's |
| R | 18.61 | 58.47 | 8⅝ | 58 | Avg men's (AU/UK) |
| R 1/2 | 18.80 | 59.06 | 8⅞ | 59 | Avg men's |
| S | 19.10 | 60.00 | 9⅛ | 60 | Avg men's |
| S 1/2 | 19.31 | 60.66 | 9⅜ | 61 | Avg men's |
| T | 19.51 | 61.29 | 9⅝ | 61 | Avg men's (AU/UK) |
| T 1/2 | 19.84 | 62.33 | 10 | 62 | Avg men's |
| U | 20.02 | 62.89 | 10¼ | 63 | Large men's |
| U 1/2 | 20.20 | 63.46 | 10½ | 63 | Large men's |
| V | 20.32 | 63.84 | 10⅝ | 64 | Large men's |
| V 1/2 | 20.68 | 64.97 | 11 | 65 | Large men's |
| W | 20.76 | 65.22 | 11⅛ | 65 | Large |
| W 1/2 | 20.94 | 65.78 | 11⅜ | 66 | Large |
| X | 21.18 | 66.54 | 11⅝ | 67 | Extra large |
| X 1/2 | 21.30 | 66.92 | 11⅞ | 67 | Extra large |
| Y | 21.49 | 67.51 | 12 | 68 | Extra large |
| Y 1/2 | 21.69 | 68.14 | 12¼ | 68 | Extra large |
| Z | 21.89 | 68.77 | 12½ | 69 | XXL |
| Z+1/2 | 22.10 | 69.43 | 12¾ | 69 | XXL |
| Z+1 | 22.33 | 70.15 | 13 | 70 | XXL |
| Z+1½ | 22.60 | 71.00 | 13½ | 71 | XXL |
🟧 Orange = typical women's range (AU/UK: M–P) | 🟦 Blue = typical men's range (AU/UK: R–T) | Source: Class A Jewellers AU / Larson Jewelers
Three completely different sizing systems are used around the world, and knowing how they relate to each other is essential for cross-border ring shopping.
Used by Australia, the UK, Ireland, New Zealand, and South Africa. Sizes are expressed as letters of the alphabet starting from approximately A, with full sizes and half sizes (e.g., N, N½). Each half-size increment adds 0.75 mm to the inner circumference. The most common commercial sizes range from G to Z+1½. This is the oldest and most traditional of the three systems, originating in British jewellery trade standards. AU = UK exactly — same letters, same measurements.
Used by the United States, Canada, and Mexico. Sizes are expressed as numbers from approximately 1 through 13, with quarter-size increments (e.g., 6, 6¼, 6½, 6¾). The US system has no direct mathematical relationship with the AU/UK letter system — conversion requires a lookup table. Average US women's ring size is approximately 6–7 (equivalent to AU/UK N–P), and average US men's ring size is approximately 9–10 (equivalent to AU/UK S–T½).
Used across continental Europe and specified in the ISO 8653 standard. EU sizes are expressed as the inner circumference of the ring in millimetres, rounded to the nearest whole number (e.g., EU 53 = 53 mm circumference = AU/UK size N). This makes the EU system the most technically transparent — the size number literally is the finger measurement. EU sizes typically range from 44 to 76 for commercial rings. Also sometimes called the "French" or "ISO" ring sizing system.
Average AU/UK women's ring size: N (16.92 mm / 53.16 mm circ) = US 6½ = EU 53. Common women's range: M to P. Average AU/UK men's ring size: T (19.51 mm / 61.29 mm circ) = US 9⅝ = EU 61. Common men's range: R to U. Each full letter step = +1.5 mm circumference. Each half letter step = +0.75 mm circumference. To jump from AU/UK to EU: use the circumference in mm (e.g., size N = 53.16 mm ≈ EU 53). To convert AU/UK to US: use our calculator or the table above.
An Australian shopper buying from a UK Etsy seller, or a UK buyer ordering from an Australian jewellery site, can use the same letter size directly — no conversion step needed. Where conversion IS needed is when ordering from US retailers (convert to US number) or European brands (convert to EU number). Our calculator handles both automatically from any AU/UK letter input, making international online ring purchases accurate and stress-free.
Secretly measuring a partner's ring size for a surprise engagement ring is one of the most common use cases. Borrow one of their existing rings, measure the inner diameter with a ruler in mm, then use our circumference finder tab to identify the AU/UK letter size. Average women's sizes in Australia and the UK are N to O — a jeweller's most-stocked range. Most engagement ring brands allow free resizing within 30 days if the size is slightly off.
A ring bought in the UK that needs resizing in Australia (or vice versa) uses the same letter sizing system, so the jeweller quote is immediately comparable. A UK jeweller and an Australian jeweller both know exactly what "size P" means. The complication arises when resizing a ring originally sized in US or EU measurements — our tool converts those back to the shared AU/UK letter size so local jewellers can work with the correct target size.
Buying a ring as a gift — for a birthday, anniversary, or Christmas — requires knowing the recipient's size without asking. Partners, family members, and friends in Australia and the UK share a common letter-size reference. If someone says "I'm a size M" in Australia, a UK buyer knows exactly what size to order. For less certain situations, many Australian and UK jewellers sell adjustable or resize-once gift rings in "average" sizes (N for women, T for men) as a practical starting point.
Vintage rings sold at UK antique markets, Australian estate sales, or online platforms like eBay are typically labelled in the shared AU/UK letter system. A ring marked "P" from a 1970s UK estate collection is the same size P used by Australian jewellers today — the letter system has been consistent for over a century. For very old rings (pre-1900s), minor variations in sizing standards occasionally existed regionally, so always verify the inner diameter in mm for antique pieces before purchasing.
Jewellery retailers, wholesalers, and manufacturers in Australia and the UK routinely need to communicate ring sizes across borders and with international suppliers. Converting a European manufacturer's EU size 56 to AU/UK size P, or translating a US customer's size 7½ to AU/UK size P, are everyday trade tasks. A reliable full-range conversion chart covering G to Z+1½ with all three international equivalents is an essential reference tool for any jewellery business serving Australian and UK markets in 2026.
While AU and UK ring sizes are the same system, minor variations exist between different ring size charts published by different jewellers — particularly in the US size equivalents column. The measurements in our chart follow the widely cited Class A Jewellers AU standard. For the most precise fit, always have your ring professionally sized at a local jeweller using a ring mandrel and ring sizer set, especially for expensive rings like engagement rings and wedding bands. Use this online tool as a guide; professional sizing is always recommended for final purchase.
One of Australia's largest jewellery retailers, Shiels provides a comprehensive Australian ring size chart and professional sizing guide. Their chart confirms that Australian ring sizes use the same letter system as the UK, with sizes from G to Z. Their guide also explains how to measure at home and what to consider when buying rings for different finger types.
View Chart →Class A Jewellers' international ring size conversion chart is one of the most cited AU/UK-to-US ring size references in Australia, providing exact inner diameter and circumference measurements in both mm and inches for all sizes from G to Z+1½. This is the source data used to build our conversion table above — a trusted industry reference for Australian jewellers.
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