Ever stood in a dimly lit dressing room in Sydney, clutching a pair of jeans that should fit, only to realize you can’t get them past your knees? Or maybe you’re scrolling through an iconic Aussie boutique online, heart set on a linen dress, but the "Size 10" label feels like a total gamble. It’s frustrating. Shopping for an Australian size to US equivalent isn't just about math. It’s about understanding two completely different garment philosophies.
You’ve probably heard the "subtract two" rule. It’s the golden nugget of wisdom passed around travel forums. If you’re a Size 10 in Australia, you’re a Size 6 in the US. Simple, right?
Well, not really.
The reality is messier. Between vanity sizing in American malls and the trend-focused, often slimmer cuts of Australian "boutique" culture, that two-size gap is more of a suggestion than a law. Honestly, if you rely solely on a basic conversion chart, you’re going to end up paying for a lot of international return shipping.
The Basic Math of Australian Size to US Conversions
Let’s get the foundational stuff out of the way first. Australia follows a sizing convention similar to the UK. Most major brands like Cotton On, Zimmermann, or Glassons use even numbers starting from 4 or 6.
Standard conversion usually looks like this: An Australian 4 is a US 0. An Australian 6 is a US 2. An Australian 8 is a US 4. You see the pattern. It continues up the scale, where an AU 16 usually maps to a US 12.
But here’s where it gets weird.
If you go into a Target in Ohio and grab a Size 8, it’s likely going to feel much roomier than an AU 12 from a high-end designer in Melbourne. Why? Because American "vanity sizing" has shifted the goalposts over the last twenty years. A Size 6 today in the US is often what a Size 10 used to be in the 1970s. Australia has done this too, but to a lesser extent, especially with their mid-to-high-end labels which tend to stay "true" to a smaller, more athletic block.
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Why the "Subtract Two" Rule Fails
It fails because of "ease." In garment construction, ease is the amount of space between the fabric and your skin.
American brands often design for a "comfort fit." Think about brands like Gap or Old Navy. They want you to feel good, so they cut generously. Australian brands, particularly the ones gaining global fame like Aje or With Jéan, often design for a "fashion fit." This means higher armholes, narrower shoulders, and less forgiveness in the waist.
If you’re curvy—specifically in the hips or bust—that "subtract two" rule might leave you breathless. Literally. You might find that while your waist fits the US 6 (AU 10), your hips are screaming for a US 8 (AU 12).
Shoes Are a Different Beast Entirely
If you thought dresses were confusing, welcome to the world of footwear.
Australian women’s shoe sizing is technically the same as US sizing. Mostly. If you wear a 9 in Sydney, you wear a 9 in New York. However, many Australian retailers actually stock European sizes (37, 38, 39) or use a slightly narrower last.
For men, it’s a total disaster.
Australian men’s shoe sizes usually follow the UK system. This means if you are a US 10, you are actually an Australian 9. If you forget this while buying a pair of R.M. Williams boots, you’re going to be swimming in them. Always check if the "AU" size listed is using the US or UK scale, because in Australia, it depends entirely on the brand's heritage.
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Real World Examples: Brand Specific Quirks
Let's look at the heavy hitters.
Zimmermann: This is a luxury powerhouse. They don't even use standard AU sizing for everything. They use 0, 1, 2, 3. A Zimmermann 0 is roughly an AU 6 or 8 (US 2 or 4). Because their pieces are often structured with zero stretch, people usually size up.
Showpo / Princess Polly: These are the giants of fast fashion. They target a younger demographic. Their AU 8 is almost exactly a US 4, but the fabric is usually stretchy. You can be more "brave" with your sizing here.
Country Road: This is an Australian staple. They are notorious for "generous" sizing. An AU 10 at Country Road feels like a US 8, or even a US 10 in some styles. It’s the closest thing Australia has to the American "mall fit."
Measuring Your Way Out of the Mess
Stop looking at the number on the tag. It’s lying to you.
The only way to win the Australian size to US game is to know your measurements in centimeters. Yes, centimeters. Australia is a metric country. While American sites give you inches, an Aussie size chart will almost always prioritize cm.
Grab a soft measuring tape. Measure three points:
- Bust: The fullest part (usually across the nipples).
- Waist: The narrowest part of your torso (usually an inch above the belly button).
- Hip: The widest part of your butt/thighs.
If an Australian site says an AU 12 is for a 75cm waist, and you’re a 30-inch waist (which is about 76cm), you’re right on the edge. In that case, always size up. Australian return shipping from the US can cost $30 to $50. It’s better to have a seamstress take a dress in than to have a garment you can't zip up.
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The Men’s Size Shift
Men actually have it easier, but only for clothes.
Suits and shirts in Australia are often sized in inches, just like the US. A 40R jacket in Sydney is a 40R jacket in Los Angeles. The difference is the "drop." Australian "slim fit" is significantly slimmer than American "slim fit."
If you’re a guy who buys "Standard Fit" in the US, you’ll likely need to go up one chest size in Australia to get the same level of comfort.
Sustainability and the Cost of Getting it Wrong
There's a hidden cost to the sizing confusion.
When we guess our Australian size to US conversion and get it wrong, we contribute to a massive environmental problem. Returns often don't go back on the shelf. In international e-commerce, returns are frequently liquidated or sent to landfills because the logistics of shipping a single item back across the Pacific are too expensive.
Being precise isn't just about looking good. It’s about being a conscious consumer.
Actionable Steps for a Perfect Fit
- Check the Model’s Stats: Most Australian boutiques (like Sabo Skirt or Spell) list the model’s height and the size she is wearing. If she’s 5'10" wearing an AU 8 and the hem hits her mid-thigh, and you’re 5'4", that "mini" dress will be a "midi" on you.
- The "Fabric Content" Trick: Look for Elastane or Spandex. If a garment is 100% linen or 100% cotton, there is zero give. If you are between an AU 10 and AU 12, go for the 12. If it has 2% Elastane, you can probably squeeze into the 10.
- Read the "Size & Fit" Tab: Ignore the general size guide. Look for the "Product Measurements." This tells you the actual dimensions of the specific garment, not the body it's intended for.
- Use Social Media: Search the brand on TikTok or Instagram. Look for "haul" videos from creators who share their measurements. Seeing a "Real-life US 8" try on an "Australian 12" is worth a thousand size charts.
- Convert Your Shoes Correctly: For men, assume AU is UK sizing unless stated otherwise. For women, assume they are the same, but always check the CM/MM length of the insole.
The "two-size difference" is a helpful starting point, but it's not a rule of law. Treat it as a hypothesis. Test it against your actual measurements and the specific vibe of the brand. Buying Australian labels is a great way to access unique styles that aren't saturated in the US market—just make sure you've got your measuring tape handy before you hit "checkout."