Convert AU to US Bra Size: Add 22 to Band for Brides
To convert an AU bra size to US, add 22 to your AU band number (AU 12 becomes US 34) and match your cup letter directly for A through D. Above a D cup, the alphabets split, so an AU E often becomes a US DDD or F depending on the brand. Always check the retailer’s own size chart before you buy.
TL;DR:
- Converting AU to US bra sizes involves adding 22 to the AU band number and matching cup letters for A to D, but larger cups vary by brand beyond D.
- The band conversion relies on centimetre measurement ranges, with the add-22 rule serving as a quick estimate rather than a precise measure.
- Cup size labels align across AU, UK, and US for A to D, but beyond that, alphabet differences mean you must check brand-specific sizing and bust measurements.
- Accurate self-measurement of underbust and overbust in centimetres ensures better size conversion and fit, especially when shopping for bridal lingerie.
- Sister sizing, by moving one band size up or down and adjusting the cup letter, helps find better fit options when exact converted sizes are unavailable.
Table of Contents
- AU to US bra size chart: band and cup lookup
- How do you convert any AU bra size to US?
- How to measure yourself for an accurate conversion
- Common AU to US bra size conversion mistakes
- AU to US bra size examples people actually search for
- Why trust this AU to US bra sizing guide?
- Why the standard conversion chart isn’t the full story
- Getting your bridal fit right after converting sizes
- Sources
- FAQ
AU to US bra size chart: band and cup lookup
The band conversion follows a simple pattern because Australian sizing uses even dress-size numbers rather than direct centimetre measurements. AU 8 corresponds roughly to US 30, AU 10 roughly to US 32, and so on up the scale in steps of two. This mapping is based on the underbust centimetre ranges each dress-size band represents, not a literal inch-for-inch translation, according to Bra-calculator.
Cup letters are where things get interesting. From A to D, Australian, UK, and US cup labels line up almost exactly, so an AU 12C sits comfortably as a US 34C. Past DD, the alphabets diverge because manufacturers in each country adopted different labelling conventions for larger volumes. An AU DD cup often becomes a US DD or E, and an AU E cup frequently shows up as a US DDD or F, according to bra-calculator.com’s Australian bra size calculator.
The legend for reading this table: convert the band number first using the “add 22” shortcut, then convert the cup by counting its alphabetical position rather than matching the letter itself. Treat the add-22 trick as a fast lookup, not a precise measurement, because it assumes your underbust falls neatly within the standard range for that band. Specialist Australian retailers extend their charts well past D, covering DD through KK for fuller busts, and those extended tables are worth checking directly if you sit in that range, per Brava Lingerie’s size chart.
How do you convert any AU bra size to US?
You don’t need to memorise a chart if you know the method behind it. Four steps get you from any Australian size to its US equivalent, whether or not it’s listed in a standard table.
- Measure your underbust in centimetres and match it against the ranges in the table above to confirm your actual AU dress-size band, rather than trusting whatever size you last bought.
- Convert the band using the add-22 shortcut. AU 12 becomes 34, AU 14 becomes 36. This works because AU bands step in even numbers (in centimetres) while US bands step in inches, and the two numbering systems happen to offset by 22 across most of the size range, per Bra-calculator.
- Convert the cup by position, not by letter. Count where your cup sits alphabetically (A is 1st, B is 2nd, C is 3rd, D is 4th) and match that position in the US sequence. This matters because US brands sometimes use DDD where AU uses E or F for the same position.
- Try a sister size if the exact match isn’t in stock. Moving up one band and down one cup letter (or vice versa) usually gives a comparable fit, since band and cup volume trade off against each other, according to Bra-calculator.
Pro Tip: If a US brand’s chart lists both DDD and E as separate cups, don’t assume they’re identical. Compare the actual bust and underbust centimetre ranges listed for each cup rather than trusting the letter alone.
How to measure yourself for an accurate conversion
Getting the underbust and overbust measurements right matters more than any formula, because the whole conversion chain starts from these two numbers.
- Underbust: wrap the tape directly under your bust, parallel to the floor, snug enough to sit firmly without digging in.
- Overbust (bust): measure across the fullest part of your bust, keeping the tape level and relaxed, not compressed.
- Tension check: you should be able to slide two fingers under the tape at both points. Any tighter and the reading skews small.
- Cup calculation: subtract your underbust from your overbust. Each 2.5 cm (roughly 1 inch) of difference equals one cup letter, so a 10 cm difference typically lands you around a D cup.
Measurement precision matters more than most people realise. Calculators built for bra sizing recommend working in increments as small as 0.5 cm or a quarter inch, because a rounding error at the measuring stage compounds into a full cup-size mismatch by the time it’s converted, according to Calculator.
Re-measure your bust and underbust regularly, especially after weight changes, pregnancy, or surgery. Avoid pulling the measuring tape too tightly around your ribcage as it can result in a smaller band measurement and an inaccurately larger cup size estimate.
Common AU to US bra size conversion mistakes
Most sizing complaints trace back to one of a handful of predictable errors, and every one of them is avoidable once you know what to check.
- Treating the AU number as a direct centimetre measurement. It isn’t. AU 12 is a dress-size label representing a range of underbust measurements, not a direct measurement in centimetres, and shoppers who skip the conversion step end up guessing.
- Assuming letters match past DD. They frequently don’t. AU 12DD can land as US 34DD or 34E, and AU 12E can land as US 34DDD or 34F, depending entirely on which brand’s chart you’re reading, per bra-calculator.com.
- Skipping the brand’s own size chart. Underbust and overbust cm ranges vary between labels even at the “same” size, especially past a D cup, where the construction differs more between manufacturers.
- Ignoring sister sizes on borderline measurements. If your underbust sits right between two bands, sizing up the band and down the cup (or the reverse) often solves the problem faster than searching for an “exact” match.
Because AU/NZ bands step in five centimetre increments while US bands step in whole inches, small mismatches are baked into the system rather than being a fitting error on your part, notes Triumph’s guide to AU versus US and EU sizing.
Pro Tip: When a US brand only stocks a DDD cup and your AU size converts to an E, check the bust measurement range listed for that DDD cup before ruling it out. The label rarely tells the full story.
AU to US bra size examples people actually search for
Concrete examples make the method click faster than any formula on its own.
- AU 12C → US 34C. The band converts with the add-22 rule (12 + 22 = 34), and C sits within the A to D range where letters align cleanly across both systems.
- AU 12DD → US 34DD or 34E. The band still converts to 34, but the cup depends on the brand’s own lettering. Some US labels keep DD, others jump straight to E for the same volume.
- AU 12E → US 34DDD or 34F. This is where confusion peaks. AU’s E sits one position above DD, and different US brands use either DDD or F to represent that same position, according to bra-calculator.com.
- Borderline example: AU 14 underbust reading close to 78 cm. If you’re right on the boundary between AU 12 and AU 14, try a sister size, an AU 14D behaves similarly to an AU 12DD in overall volume, so both are worth trying before you settle.
Why trust this AU to US bra sizing guide?
Australian bridal accessories stores stock bridal jewellery, hairpieces, and luxury bridal lingerie alongside handmade wedding garters. Fitting a bride correctly, especially under a fitted gown, means understanding how sizing translates across markets when brides shop US and UK lingerie brands for their wedding day or honeymoon.
Every product listing on the site notes band and cm ranges where relevant, so shoppers can cross-check their measurements against the actual garment rather than relying on a size label alone. If you’re choosing a strapless bra for your wedding gown, get your underbust and overbust measurements sorted first using the method above, then compare them against the specific product’s size notes before you order.
Why the standard conversion chart isn’t the full story
Most bra size charts stop at the band-plus-cup conversion and call it done. That’s fine for a straightforward AU 10B or AU 12C, but it quietly fails the exact shoppers who need it most: anyone above a D cup, which by some fitting estimates is the majority of adult women.
The real issue isn’t the maths. Add 22 to the band, count cup positions, done. The real issue is that alphabets were never standardised for volume past D, so every conversion above that point is really asking “what does this particular brand call this particular measurement?” rather than “what is the true US equivalent?” A chart can’t answer that. Only the specific brand’s own cm ranges can.
If you take one thing from this guide, prioritise the measuring tape over the label every time, especially when shopping bridal lingerie from an unfamiliar brand ahead of a fitting deadline. Sister sizing is the safety net most shoppers don’t know exists, and it solves more fit problems than obsessing over which letter is “correct.”
— The Wedding Garter
Getting your bridal fit right after converting sizes
Once you’ve worked out your converted size, the next challenge is finding a bridal piece that actually holds its shape under a fitted gown, not just any bra in the right numbers. There are bridal-specific styles built for that job, including underwire bustiers and sheer lace pieces designed to sit smoothly under wedding dresses rather than general everyday lingerie repurposed for the day.
The Romantic Lace Underwire Bridal Bustier and the Delicate Sheer Lace Bridal Bustier Lingerie both list their own underbust ranges on the product page, worth checking against your converted measurements rather than assuming the number alone guarantees a fit. If you’re after something softer for the morning of the wedding or the night after, the Luxury White Lace Lingerie Chemise For Brides is sized more forgivingly but still benefits from a quick measurement check first.
Unsure which size to order, or torn between two options on the borderline? Reach out to customer support before you check out. It’s a faster fix than ordering two sizes and returning one.
Sources
- Best Australian Bra Size Chart: AU to US, UK & EU Conversion 2026
- Bra size chart | Brava Lingerie
- AU/NZ vs EU & US bra sizing | Triumph Lingerie
FAQ
What is the US equivalent of an Australian bra size?
Add 22 to the AU band number to get the US band (AU 12 becomes US 34), and match the cup letter directly for A through D. Above D, check the brand’s chart, as letters can diverge.
What is a 34C bra size in Australia?
A US 34C converts to an AU 12C. The band drops by 22 (34 minus 22 equals 12) and the cup stays the same, since C sits within the range where AU, UK, and US letters align.
What is a 32A bra size in Australia?
A US 32A converts to an AU 10A. Subtract 22 from the band number and keep the cup letter unchanged, since A cups match across all three systems.
How do I know my correct US bra size from my AU measurements?
Measure your underbust and overbust in centimetres, confirm your AU band from the ranges in the conversion table above, then apply the add-22 band shortcut and convert your cup by position rather than letter.
Why do AU and US cup sizes differ above a D cup?
AU and US brands never standardised cup lettering for larger volumes, so an AU E cup can appear as a US DDD or F cup depending on the brand, according to bra-calculator.com. Always check the specific retailer’s underbust and cup range before buying.
