Full Ring Size Conversion Guide Australia – AU to US, EU, UK, Japan & India

Full Ring Size Conversion Guide Australia

Complete AU/UK to US, EU, Japan & India ring size conversions — all 29 sizes A to Z+3 with diameter in mm, circumference, and international equivalents

🇦🇺 Australian / UK Standard 📏 Sizes A – Z+3 🇺🇸 US / Canada 🇪🇺 EU / ISO 🇯🇵 Japan · 🇮🇳 India

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Total AU Sizes
A to Z+3

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International
Systems Covered

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N / T

Avg Women / Men
AU Ring Size

🔄

AU=UK

Australian & UK
Sizes Are Identical

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Ring Size Conversion Calculator

Enter your finger measurement to instantly find your Australian ring size & all international conversions

Your Australian / UK Ring Size

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Full AU to US, EU, Japan & India Conversion

🇦🇺 AU / UK	🇺🇸 US / Canada	🇪🇺 EU / ISO	🇯🇵 Japan	🇮🇳 India	⌀ Diameter (mm)	📏 Circ. (mm)
A	0.5	38	1	—	12.0 mm	37.8 mm
B	1	38.5	1	—	12.3 mm	38.5 mm
C	1.5	39	2	—	12.5 mm	39.3 mm
D	2	40	3	—	12.8 mm	40.0 mm
E	2.5	40.5	4	—	13.0 mm	40.8 mm
F	3	41	5	1	13.2 mm	41.5 mm
G	3.5	42	6	2	13.5 mm	42.3 mm
H	4	43	7	3	13.7 mm	43.0 mm
I	4.25	43.5	7	4	13.9 mm	43.8 mm
J	4.75	44	8	5	14.2 mm	44.5 mm
K	5.25	45	9	7	14.4 mm	45.3 mm
L	5.5	46	10	8	14.6 mm	46.0 mm
M	6	46.5	11	9	14.9 mm	46.8 mm
N ⭐	6.5	47	12	10	15.1 mm	47.5 mm
O	7	48	13	11	15.3 mm	48.3 mm
P	7.5	49	14	13	15.6 mm	49.0 mm
Q	8	49.5	15	14	15.8 mm	49.8 mm
R	8.5	50	15	14	16.1 mm	50.5 mm
S	9	51	16	15	16.3 mm	51.3 mm
T ⭐	9.5	52	17	16	16.6 mm	52.0 mm
U	10	52.5	18	17	16.8 mm	52.8 mm
V	10.5	53	19	18	17.0 mm	53.5 mm
W	11	54	20	19	17.3 mm	54.3 mm
X	11.5	55	21	20	17.5 mm	55.0 mm
Y	12	55.5	22	21	17.8 mm	55.8 mm
Z	12.5	56	23	22	18.0 mm	56.5 mm
Z+1	13	57	24	23	18.2 mm	57.3 mm
Z+2	13.5	58	25	24	18.5 mm	58.0 mm
Z+3	14	58.5	26	25	18.7 mm	58.8 mm

⭐ AU N = Most common women's size (US 6.5 · EU 47)

⭐ AU T = Most common men's size (US 9.5 · EU 52)

🇦🇺 AU sizes = 🇬🇧 UK sizes — identical system

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Visual Ring Size Scale — All 29 Sizes

Proportional circles showing the relative diameter of each AU ring size from A to Z+3. Compare sizes side by side to understand the real-world scale.

⚠️ Proportional only — not exact pixel-to-mm. Always use a ruler for accurate sizing.

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Key Sizes Visual Comparison

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Understanding Each Ring Size System

🇦🇺

Australian / UK

Uses letters A–Z+3. Australia and the UK use the exact same system. Most common women's: N. Most common men's: T.

🇺🇸

US / Canada

Uses numbers 0–16 in half-step increments. US size 6.5 = AU N (women's avg). US size 9.5 = AU T (men's avg).

🇪🇺

EU / ISO

Uses the ring's inner circumference in mm as the size number. EU 47 = AU N. EU 52 = AU T. Most precise system.

🇯🇵

Japan

Uses numbers 1–30. Similar to US but starts lower. Japan 12 = AU N. Japan 17 = AU T. Popular across East Asia.

🇮🇳

India

Uses numbers 1–30, slightly offset from Japan. India 10 = AU N. India 16 = AU T. Used across South Asia.

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mm / ISO Standard

The most universal method — measure circumference or diameter in mm. Works with any sizing system worldwide without conversion charts.

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Ring Size Conversion Formulas

📐 Key Formulas

Diameter → Circumference (EU Size)

EU Size = Circumference (mm) = Diameter (mm) × 3.14159

Example: 15.1 mm × 3.14159 = 47.4 mm → EU 47 → AU Size N

Circumference → Diameter

Diameter (mm) = Circumference (mm) ÷ 3.14159

Example: 52.0 mm ÷ 3.14159 = 16.56 mm → AU Size T

Inches → Millimetres

mm = inches × 25.4

Example: 0.654″ × 25.4 = 16.6 mm diameter → AU Size T

US Size → AU/UK Approximate

AU Size ≈ US + approx 2 letter steps (use chart above)

Example: US 6.5 → AU N · US 9.5 → AU T · Always verify with chart

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Quick Conversion Reference

AU / UK	🇺🇸 US	🇪🇺 EU	🇯🇵 Japan	⌀ mm	Typical Wearer
H	4	43	7	13.7 mm	Small Women
J	4.75	44	8	14.2 mm	Women
L	5.5	46	10	14.6 mm	Women
N ⭐	6.5	47	12	15.1 mm	Most Common ♀
P	7.5	49	14	15.6 mm	Unisex
R	8.5	50	15	16.1 mm	Men
T ⭐	9.5	52	17	16.6 mm	Most Common ♂
V	10.5	53	19	17.0 mm	Men
X	11.5	55	21	17.5 mm	Large Men
Z	12.5	56	23	18.0 mm	Large Men

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Ring Size Conversion Tips

🇦🇺AU = UK exactly — Australian and UK ring sizes are the same alphabetical system. If you know your UK size, you already know your AU size.
🌡️EU sizes are the most precise — the EU system uses the actual inner circumference in mm as the size number, making it the least ambiguous system for custom or bespoke rings.
⚠️Half sizes vary between brands — US half sizes don't always align exactly across brands. When converting from US to AU, always verify against the circumference (mm) column rather than relying on a simple formula.
📏mm is universal — when ordering internationally or from an online jeweller, always provide your diameter or circumference in mm alongside the size letter. This eliminates any conversion ambiguity.
🔁Always size up when between sizes — if you fall between two AU letter sizes, always order the larger one. A ring that is slightly too large can be resized or worn with a ring adjuster, while a ring that is too small cannot be worn at all.
💎Wide bands need a larger size — for any band 6 mm or wider (standard for men's wedding rings), order one full AU letter size larger than your measured size for a comfortable custom fit.
🔧Titanium & tungsten cannot be resized — if ordering in these materials, measure your finger at least 3 times and confirm your exact custom size before placing the order.

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Frequently Asked Questions

Are Australian ring sizes the same as UK ring sizes?▼

Yes — Australia and the UK use the exact same alphabetical ring size system (A through Z+3). An AU Size N is identical to a UK Size N. No conversion is needed between the two countries.

What is AU Size N in US and EU ring sizes?▼

AU Size N = US 6.5 and EU 47. It has a diameter of 15.1 mm and a circumference of 47.5 mm. Size N is the most common women's ring size in Australia.

What is AU Size T in US and EU ring sizes?▼

AU Size T = US 9.5 and EU 52. It has a diameter of 16.6 mm and a circumference of 52.0 mm. Size T is the most common men's ring size in Australia.

What does the EU ring size number mean?▼

The EU (ISO) ring size number equals the ring's inner circumference in millimetres. EU 47 means the inner circumference is 47 mm. This makes it the most precise and universal sizing system — no conversion formula needed, just measure your finger circumference directly.

How do I convert my US ring size to Australian?▼

Use the Full Conversion Table above. Common conversions: US 5 = AU K, US 6 = AU M, US 6.5 = AU N, US 7 = AU O, US 8 = AU Q, US 9 = AU S, US 9.5 = AU T, US 10 = AU U, US 11 = AU W, US 12 = AU Y.

Why does my ring size differ between countries?▼

Different countries developed their own independent ring sizing standards before international coordination existed. The AU/UK, US, EU, Japanese, and Indian systems all use different scales and reference points but all measure the same thing — the inner diameter or circumference of the ring. Use the mm measurement as your universal reference to convert accurately between any system.

What is the best way to find my ring size for an international order?▼

Measure your finger circumference in mm using the paper/string method, enter it in the calculator above, then note both your AU letter size and your EU (mm circumference) size. When ordering from an international jeweller, always provide the circumference in mm — this is universally understood and eliminates any conversion errors.