AU to US Ring Size Conversion – Australian to American Ring Size Chart

AU to US Ring Size Conversion

Convert Australian ring sizes to US sizes instantly — full chart with diameter in mm, circumference, half sizes, and a free AU to US ring size converter tool

🇦🇺 Australian Letter Sizes 🇺🇸 US Numeric Sizes 📏 Sizes G – Z+1.5 📐 mm Measurements ½ Half Sizes Included

🇦🇺

Avg AU Women's
Ring Size

🇺🇸

6½

Equiv. US Women's
Ring Size

📊

40+

Sizes in
Conversion Chart

📐

Size Up If
Between Sizes

🔄

AU to US Ring Size Converter

Select your Australian ring size to instantly find the equivalent US ring size

Australian Size

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Equivalent US Size

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Complete AU to US Ring Size Chart

🇦🇺 AU / UK Size	🇺🇸 US Size	Diameter (mm)	Circumference (mm)	Typical Wearer
G	3⅜	14.36 mm	45.1 mm	Small Women
G½	3⅝	14.56 mm	45.7 mm	Small Women
H	3¾	14.65 mm	46.0 mm	Small Women
H½	4	14.86 mm	46.7 mm	Small Women
I	4¼	15.04 mm	47.3 mm	Women
I½	4½	15.27 mm	48.0 mm	Women
J	4⅝	15.40 mm	48.4 mm	Women
J½	5	15.70 mm	49.3 mm	Women
K	5⅛	15.80 mm	49.6 mm	Women
K½	5⅜	16.00 mm	50.3 mm	Women
L	5½	16.10 mm	50.6 mm	Women
L½	5⅞	16.41 mm	51.6 mm	Women
M	6	16.51 mm	51.9 mm	Popular ♀
M½	6¼	16.71 mm	52.5 mm	Popular ♀
N ⭐	6½	16.92 mm	53.2 mm	Most Common ♀
N½	6¾	17.13 mm	53.8 mm	Popular ♀
O	7	17.35 mm	54.5 mm	Women / Men
O½	7¼	17.45 mm	54.8 mm	Women / Men
P	7½	17.75 mm	55.8 mm	Women / Men
P½	7¾	17.97 mm	56.5 mm	Women / Men
Q	8	18.19 mm	57.2 mm	Men
Q½	8¼	18.35 mm	57.7 mm	Men
R	8⅝	18.61 mm	58.5 mm	Men
R½	8⅞	18.80 mm	59.1 mm	Men
S	9⅛	19.10 mm	60.0 mm	Men
S½	9⅜	19.31 mm	60.7 mm	Men
T ⭐	9⅝	19.51 mm	61.3 mm	Most Common ♂
T½	10	19.84 mm	62.3 mm	Men
U	10¼	20.02 mm	62.9 mm	Men
U½	10½	20.20 mm	63.5 mm	Men
V	10⅝	20.32 mm	63.8 mm	Large Men
V½	11	20.68 mm	65.0 mm	Large Men
W	11⅛	20.76 mm	65.2 mm	Large Men
W½	11⅜	20.94 mm	65.8 mm	Large Men
X	11⅝	21.18 mm	66.5 mm	XL
X½	11⅞	21.30 mm	66.9 mm	XL
Y	12	21.49 mm	67.5 mm	XL
Y½	12¼	21.69 mm	68.1 mm	XL
Z	12½	21.89 mm	68.8 mm	XL
Z½	12¾	22.10 mm	69.4 mm	XXL
Z+1	13	22.33 mm	70.2 mm	XXL
Z+1.5	13½	22.60 mm	71.0 mm	XXL

⭐ AU N = US 6½ — Most common women's size

⭐ AU T = US 9⅝ — Most common men's size

🟡 Highlighted rows = most popular sizes

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AU vs US Sizing: Key Differences

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Australian (AU / UK) System

Uses letters from A to Z+3. Half sizes are written as "G½", "H½" etc. Australia uses the same standard as the United Kingdom, so AU = UK sizing.

🇺🇸

US / Canada System

Uses numbers from 3 to 13+, often in ¼ increments (e.g. 6, 6¼, 6½, 6¾). US sizes roughly correspond to whole and fractional numbers based on inner circumference.

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How the Conversion Works

Both systems are based on the inner circumference (mm) of the ring. Each AU letter step is approximately 1.25 mm in circumference, equivalent to roughly ½ a US size step.

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Between Sizes?

If your measurement falls between two sizes, always size up — especially for wider bands, which fit tighter than narrow rings of the same size.

📐 Quick Reference Formula

AU Letter → Approximate US Number

US Size ≈ (Inner Circumference in mm − 36.5) ÷ 2.55

Example: AU N → 53.2 mm → (53.2 − 36.5) ÷ 2.55 = 6.55 ≈ US 6½

Diameter → Circumference

Circumference (mm) = Diameter (mm) × π (3.14159)

Example: 16.92 mm × 3.14159 = 53.2 mm → AU N = US 6½

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Ring Sizing Tips

🕗Measure at end of day — fingers are slightly larger in the evening due to natural swelling throughout the day.
🌡️Avoid measuring when cold — fingers shrink in cold temperatures, which can give an inaccurately small size reading.
💍Wider bands fit tighter — if ordering a band wider than 6mm, go up half a size from your measured size in both AU and US sizing.
☝️Measure the correct finger — ring finger sizes differ between your left and right hand. Always measure the specific finger you'll wear the ring on.
🔁Measure 3 times — take three separate measurements and use the average. This ensures accuracy, especially if using paper or string methods.
📏Size up if in between — when your measurement falls between two AU or US sizes, always choose the larger size for comfort.

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Frequently Asked Questions

What is Australian ring size N in US size? ▾

Australian ring size N is equivalent to US size 6½. This is the most common women's ring size in Australia. It corresponds to an inner diameter of 16.92 mm and a circumference of approximately 53.2 mm.

What is Australian ring size T in US size? ▾

Australian ring size T equals US size 9⅝. Size T is the most common men's ring size in Australia, with an inner diameter of 19.51 mm and circumference of 61.3 mm.

Are Australian and UK ring sizes the same? ▾

Yes — Australian and UK ring sizes are identical. Both use the same letter-based system (A to Z+3). If you know your UK ring size, it is exactly the same as your Australian ring size.

How do I convert AU ring size to US without a chart? ▾

Measure your inner finger circumference in mm, then use the formula: US Size = (Circumference mm − 36.5) ÷ 2.55. Alternatively, use the converter tool on this page by simply selecting your AU letter size.

What is US size 7 in Australian ring size? ▾

US size 7 is equivalent to Australian size O. This corresponds to a diameter of 17.35 mm and a circumference of 54.5 mm. It's a popular unisex size that works for larger women's fingers or smaller men's fingers.

What is US size 6 in Australian ring size? ▾

US size 6 is equivalent to Australian size M. The diameter is 16.51 mm and circumference is 51.9 mm. This is one of the most popular women's ring sizes worldwide.

Do AU ring sizes include half sizes? ▾

Yes — Australian ring sizes include half sizes, written as "G½", "H½" etc. These fall exactly between two full letter sizes and are commonly stocked by Australian and UK jewellers for a more precise fit.